Merging upstream version 1.34.0.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

9 files changed, 0 insertions, 1537 deletions

diff --git a/backends/prometheus/Makefile.am b/backends/prometheus/Makefile.am
deleted file mode 100644
index 334fca81c..000000000
--- a/backends/prometheus/Makefile.am
+++ /dev/null
@@ -1,12 +0,0 @@
-# SPDX-License-Identifier: GPL-3.0-or-later
-
-AUTOMAKE_OPTIONS = subdir-objects
-MAINTAINERCLEANFILES = $(srcdir)/Makefile.in
-
-SUBDIRS = \
-    remote_write \
-    $(NULL)
-
-dist_noinst_DATA = \
-    README.md \
-    $(NULL)
diff --git a/backends/prometheus/README.md b/backends/prometheus/README.md
deleted file mode 100644
index a0460d1d8..000000000
--- a/backends/prometheus/README.md
+++ /dev/null
@@ -1,457 +0,0 @@
-<!--
-title: "Using Netdata with Prometheus"
-custom_edit_url: https://github.com/netdata/netdata/edit/master/backends/prometheus/README.md
--->
-
-# Using Netdata with Prometheus
-
-> IMPORTANT: the format Netdata sends metrics to prometheus has changed since Netdata v1.7. The new prometheus backend
-> for Netdata supports a lot more features and is aligned to the development of the rest of the Netdata backends.
-
-Prometheus is a distributed monitoring system which offers a very simple setup along with a robust data model. Recently
-Netdata added support for Prometheus. I'm going to quickly show you how to install both Netdata and prometheus on the
-same server. We can then use grafana pointed at Prometheus to obtain long term metrics Netdata offers. I'm assuming we
-are starting at a fresh ubuntu shell (whether you'd like to follow along in a VM or a cloud instance is up to you).
-
-## Installing Netdata and prometheus
-
-### Installing Netdata
-
-There are number of ways to install Netdata according to [Installation](/packaging/installer/README.md). The suggested way
-of installing the latest Netdata and keep it upgrade automatically. Using one line installation:
-
-```sh
-bash <(curl -Ss https://my-netdata.io/kickstart.sh)
-```
-
-At this point we should have Netdata listening on port 19999. Attempt to take your browser here:
-
-```sh
-http://your.netdata.ip:19999
-```
-
-_(replace `your.netdata.ip` with the IP or hostname of the server running Netdata)_
-
-### Installing Prometheus
-
-In order to install prometheus we are going to introduce our own systemd startup script along with an example of
-prometheus.yaml configuration. Prometheus needs to be pointed to your server at a specific target url for it to scrape
-Netdata's api. Prometheus is always a pull model meaning Netdata is the passive client within this architecture.
-Prometheus always initiates the connection with Netdata.
-
-#### Download Prometheus
-
-```sh
-cd /tmp && curl -s https://api.github.com/repos/prometheus/prometheus/releases/latest \
-| grep "browser_download_url.*linux-amd64.tar.gz" \
-| cut -d '"' -f 4 \
-| wget -qi -
-```
-
-#### Create prometheus system user
-
-```sh
-sudo useradd -r prometheus
-```
-
-#### Create prometheus directory
-
-```sh
-sudo mkdir /opt/prometheus
-sudo chown prometheus:prometheus /opt/prometheus
-```
-
-#### Untar prometheus directory
-
-```sh
-sudo tar -xvf /tmp/prometheus-*linux-amd64.tar.gz -C /opt/prometheus --strip=1
-```
-
-#### Install prometheus.yml
-
-We will use the following `prometheus.yml` file. Save it at `/opt/prometheus/prometheus.yml`.
-
-Make sure to replace `your.netdata.ip` with the IP or hostname of the host running Netdata. 
-
-```yaml
-# my global config
-global:
-  scrape_interval:     5s # Set the scrape interval to every 5 seconds. Default is every 1 minute.
-  evaluation_interval: 5s # Evaluate rules every 5 seconds. The default is every 1 minute.
-  # scrape_timeout is set to the global default (10s).
-
-  # Attach these labels to any time series or alerts when communicating with
-  # external systems (federation, remote storage, Alertmanager).
-  external_labels:
-      monitor: 'codelab-monitor'
-
-# Load rules once and periodically evaluate them according to the global 'evaluation_interval'.
-rule_files:
-  # - "first.rules"
-  # - "second.rules"
-
-# A scrape configuration containing exactly one endpoint to scrape:
-# Here it's Prometheus itself.
-scrape_configs:
-  # The job name is added as a label `job=<job_name>` to any timeseries scraped from this config.
-  - job_name: 'prometheus'
-
-    # metrics_path defaults to '/metrics'
-    # scheme defaults to 'http'.
-
-    static_configs:
-      - targets: ['0.0.0.0:9090']
-
-  - job_name: 'netdata-scrape'
-
-    metrics_path: '/api/v1/allmetrics'
-    params:
-      # format: prometheus | prometheus_all_hosts
-      # You can use `prometheus_all_hosts` if you want Prometheus to set the `instance` to your hostname instead of IP 
-      format: [prometheus]
-      #
-      # source: as-collected | raw | average | sum | volume
-      # default is: average
-      #source: [as-collected]
-      #
-      # server name for this prometheus - the default is the client IP
-      # for Netdata to uniquely identify it
-      #server: ['prometheus1']
-    honor_labels: true
-
-    static_configs:
-      - targets: ['{your.netdata.ip}:19999']
-```
-
-#### Install nodes.yml
-
-The following is completely optional, it will enable Prometheus to generate alerts from some Netdata sources. Tweak the
-values to your own needs. We will use the following `nodes.yml` file below. Save it at `/opt/prometheus/nodes.yml`, and
-add a _- "nodes.yml"_ entry under the _rule_files:_ section in the example prometheus.yml file above.
-
-```yaml
-groups:
-  - name: nodes
-
-    rules:
-      - alert: node_high_cpu_usage_70
-        expr: sum(sum_over_time(netdata_system_cpu_percentage_average{dimension=~"(user|system|softirq|irq|guest)"}[10m])) by (job) / sum(count_over_time(netdata_system_cpu_percentage_average{dimension="idle"}[10m])) by (job) > 70
-        for: 1m
-        annotations:
-          description: '{{ $labels.job }} on ''{{ $labels.job }}'' CPU usage is at {{ humanize $value }}%.'
-          summary: CPU alert for container node '{{ $labels.job }}'
-
-      - alert: node_high_memory_usage_70
-        expr: 100 / sum(netdata_system_ram_MB_average) by (job)
-          * sum(netdata_system_ram_MB_average{dimension=~"free|cached"}) by (job) < 30
-        for: 1m
-        annotations:
-          description: '{{ $labels.job }} memory usage is {{ humanize $value}}%.'
-          summary: Memory alert for container node '{{ $labels.job }}'
-
-      - alert: node_low_root_filesystem_space_20
-        expr: 100 / sum(netdata_disk_space_GB_average{family="/"}) by (job)
-          * sum(netdata_disk_space_GB_average{family="/",dimension=~"avail|cached"}) by (job) < 20
-        for: 1m
-        annotations:
-          description: '{{ $labels.job }} root filesystem space is {{ humanize $value}}%.'
-          summary: Root filesystem alert for container node '{{ $labels.job }}'
-
-      - alert: node_root_filesystem_fill_rate_6h
-        expr: predict_linear(netdata_disk_space_GB_average{family="/",dimension=~"avail|cached"}[1h], 6 * 3600) < 0
-        for: 1h
-        labels:
-          severity: critical
-        annotations:
-          description: Container node {{ $labels.job }} root filesystem is going to fill up in 6h.
-          summary: Disk fill alert for Swarm node '{{ $labels.job }}'
-```
-
-#### Install prometheus.service
-
-Save this service file as `/etc/systemd/system/prometheus.service`:
-
-```sh
-[Unit]
-Description=Prometheus Server
-AssertPathExists=/opt/prometheus
-
-[Service]
-Type=simple
-WorkingDirectory=/opt/prometheus
-User=prometheus
-Group=prometheus
-ExecStart=/opt/prometheus/prometheus --config.file=/opt/prometheus/prometheus.yml --log.level=info
-ExecReload=/bin/kill -SIGHUP $MAINPID
-ExecStop=/bin/kill -SIGINT $MAINPID
-
-[Install]
-WantedBy=multi-user.target
-```
-
-##### Start Prometheus
-
-```sh
-sudo systemctl start prometheus
-sudo systemctl enable prometheus
-```
-
-Prometheus should now start and listen on port 9090. Attempt to head there with your browser. 
-
-If everything is working correctly when you fetch `http://your.prometheus.ip:9090` you will see a 'Status' tab. Click
-this and click on 'targets' We should see the Netdata host as a scraped target.
-
----
-
-## Netdata support for prometheus
-
-> IMPORTANT: the format Netdata sends metrics to prometheus has changed since Netdata v1.6. The new format allows easier
-> queries for metrics and supports both `as collected` and normalized metrics.
-
-Before explaining the changes, we have to understand the key differences between Netdata and prometheus.
-
-### understanding Netdata metrics
-
-#### charts
-
-Each chart in Netdata has several properties (common to all its metrics):
-
--   `chart_id` - uniquely identifies a chart.
-
--   `chart_name` - a more human friendly name for `chart_id`, also unique.
-
--   `context` - this is the template of the chart. All disk I/O charts have the same context, all mysql requests charts
-    have the same context, etc. This is used for alarm templates to match all the charts they should be attached to.
-
--   `family` groups a set of charts together. It is used as the submenu of the dashboard.
-
--   `units` is the units for all the metrics attached to the chart.
-
-#### dimensions
-
-Then each Netdata chart contains metrics called `dimensions`. All the dimensions of a chart have the same units of
-measurement, and are contextually in the same category (ie. the metrics for disk bandwidth are `read` and `write` and
-they are both in the same chart).
-
-### Netdata data source
-
-Netdata can send metrics to prometheus from 3 data sources:
-
--   `as collected` or `raw` - this data source sends the metrics to prometheus as they are collected. No conversion is
-    done by Netdata. The latest value for each metric is just given to prometheus. This is the most preferred method by
-    prometheus, but it is also the harder to work with. To work with this data source, you will need to understand how
-    to get meaningful values out of them.
-
-    The format of the metrics is: `CONTEXT{chart="CHART",family="FAMILY",dimension="DIMENSION"}`.
-
-    If the metric is a counter (`incremental` in Netdata lingo), `_total` is appended the context.
-
-    Unlike prometheus, Netdata allows each dimension of a chart to have a different algorithm and conversion constants
-    (`multiplier` and `divisor`). In this case, that the dimensions of a charts are heterogeneous, Netdata will use this
-    format: `CONTEXT_DIMENSION{chart="CHART",family="FAMILY"}`
-
--   `average` - this data source uses the Netdata database to send the metrics to prometheus as they are presented on
-    the Netdata dashboard. So, all the metrics are sent as gauges, at the units they are presented in the Netdata
-    dashboard charts. This is the easiest to work with.
-
-    The format of the metrics is: `CONTEXT_UNITS_average{chart="CHART",family="FAMILY",dimension="DIMENSION"}`.
-
-    When this source is used, Netdata keeps track of the last access time for each prometheus server fetching the
-    metrics. This last access time is used at the subsequent queries of the same prometheus server to identify the
-    time-frame the `average` will be calculated.
-
-    So, no matter how frequently prometheus scrapes Netdata, it will get all the database data. 
-    To identify each prometheus server, Netdata uses by default the IP of the client fetching the metrics.
-     
-    If there are multiple prometheus servers fetching data from the same Netdata, using the same IP, each prometheus
-    server can append `server=NAME` to the URL. Netdata will use this `NAME` to uniquely identify the prometheus server.
-
--   `sum` or `volume`, is like `average` but instead of averaging the values, it sums them.
-
-    The format of the metrics is: `CONTEXT_UNITS_sum{chart="CHART",family="FAMILY",dimension="DIMENSION"}`. All the
-    other operations are the same with `average`. 
-
-    To change the data source to `sum` or `as-collected` you need to provide the `source` parameter in the request URL.
-    e.g.: `http://your.netdata.ip:19999/api/v1/allmetrics?format=prometheus&help=yes&source=as-collected`
-
-    Keep in mind that early versions of Netdata were sending the metrics as: `CHART_DIMENSION{}`.
-
-### Querying Metrics
-
-Fetch with your web browser this URL:
-
-`http://your.netdata.ip:19999/api/v1/allmetrics?format=prometheus&help=yes`
-
-_(replace `your.netdata.ip` with the ip or hostname of your Netdata server)_
-
-Netdata will respond with all the metrics it sends to prometheus.
-
-If you search that page for `"system.cpu"` you will find all the metrics Netdata is exporting to prometheus for this
-chart. `system.cpu` is the chart name on the Netdata dashboard (on the Netdata dashboard all charts have a text heading
-such as : `Total CPU utilization (system.cpu)`. What we are interested here in the chart name: `system.cpu`).
-
-Searching for `"system.cpu"` reveals:
-
-```sh
-# COMMENT homogeneous chart "system.cpu", context "system.cpu", family "cpu", units "percentage"
-# COMMENT netdata_system_cpu_percentage_average: dimension "guest_nice", value is percentage, gauge, dt 1500066653 to 1500066662 inclusive
-netdata_system_cpu_percentage_average{chart="system.cpu",family="cpu",dimension="guest_nice"} 0.0000000 1500066662000
-# COMMENT netdata_system_cpu_percentage_average: dimension "guest", value is percentage, gauge, dt 1500066653 to 1500066662 inclusive
-netdata_system_cpu_percentage_average{chart="system.cpu",family="cpu",dimension="guest"} 1.7837326 1500066662000
-# COMMENT netdata_system_cpu_percentage_average: dimension "steal", value is percentage, gauge, dt 1500066653 to 1500066662 inclusive
-netdata_system_cpu_percentage_average{chart="system.cpu",family="cpu",dimension="steal"} 0.0000000 1500066662000
-# COMMENT netdata_system_cpu_percentage_average: dimension "softirq", value is percentage, gauge, dt 1500066653 to 1500066662 inclusive
-netdata_system_cpu_percentage_average{chart="system.cpu",family="cpu",dimension="softirq"} 0.5275442 1500066662000
-# COMMENT netdata_system_cpu_percentage_average: dimension "irq", value is percentage, gauge, dt 1500066653 to 1500066662 inclusive
-netdata_system_cpu_percentage_average{chart="system.cpu",family="cpu",dimension="irq"} 0.2260836 1500066662000
-# COMMENT netdata_system_cpu_percentage_average: dimension "user", value is percentage, gauge, dt 1500066653 to 1500066662 inclusive
-netdata_system_cpu_percentage_average{chart="system.cpu",family="cpu",dimension="user"} 2.3362762 1500066662000
-# COMMENT netdata_system_cpu_percentage_average: dimension "system", value is percentage, gauge, dt 1500066653 to 1500066662 inclusive
-netdata_system_cpu_percentage_average{chart="system.cpu",family="cpu",dimension="system"} 1.7961062 1500066662000
-# COMMENT netdata_system_cpu_percentage_average: dimension "nice", value is percentage, gauge, dt 1500066653 to 1500066662 inclusive
-netdata_system_cpu_percentage_average{chart="system.cpu",family="cpu",dimension="nice"} 0.0000000 1500066662000
-# COMMENT netdata_system_cpu_percentage_average: dimension "iowait", value is percentage, gauge, dt 1500066653 to 1500066662 inclusive
-netdata_system_cpu_percentage_average{chart="system.cpu",family="cpu",dimension="iowait"} 0.9671802 1500066662000
-# COMMENT netdata_system_cpu_percentage_average: dimension "idle", value is percentage, gauge, dt 1500066653 to 1500066662 inclusive
-netdata_system_cpu_percentage_average{chart="system.cpu",family="cpu",dimension="idle"} 92.3630770 1500066662000
-```
-
-_(Netdata response for `system.cpu` with source=`average`)_
-
-In `average` or `sum` data sources, all values are normalized and are reported to prometheus as gauges. Now, use the
-'expression' text form in prometheus. Begin to type the metrics we are looking for: `netdata_system_cpu`. You should see
-that the text form begins to auto-fill as prometheus knows about this metric.
-
-If the data source was `as collected`, the response would be:
-
-```sh
-# COMMENT homogeneous chart "system.cpu", context "system.cpu", family "cpu", units "percentage"
-# COMMENT netdata_system_cpu_total: chart "system.cpu", context "system.cpu", family "cpu", dimension "guest_nice", value * 1 / 1 delta gives percentage (counter)
-netdata_system_cpu_total{chart="system.cpu",family="cpu",dimension="guest_nice"} 0 1500066716438
-# COMMENT netdata_system_cpu_total: chart "system.cpu", context "system.cpu", family "cpu", dimension "guest", value * 1 / 1 delta gives percentage (counter)
-netdata_system_cpu_total{chart="system.cpu",family="cpu",dimension="guest"} 63945 1500066716438
-# COMMENT netdata_system_cpu_total: chart "system.cpu", context "system.cpu", family "cpu", dimension "steal", value * 1 / 1 delta gives percentage (counter)
-netdata_system_cpu_total{chart="system.cpu",family="cpu",dimension="steal"} 0 1500066716438
-# COMMENT netdata_system_cpu_total: chart "system.cpu", context "system.cpu", family "cpu", dimension "softirq", value * 1 / 1 delta gives percentage (counter)
-netdata_system_cpu_total{chart="system.cpu",family="cpu",dimension="softirq"} 8295 1500066716438
-# COMMENT netdata_system_cpu_total: chart "system.cpu", context "system.cpu", family "cpu", dimension "irq", value * 1 / 1 delta gives percentage (counter)
-netdata_system_cpu_total{chart="system.cpu",family="cpu",dimension="irq"} 4079 1500066716438
-# COMMENT netdata_system_cpu_total: chart "system.cpu", context "system.cpu", family "cpu", dimension "user", value * 1 / 1 delta gives percentage (counter)
-netdata_system_cpu_total{chart="system.cpu",family="cpu",dimension="user"} 116488 1500066716438
-# COMMENT netdata_system_cpu_total: chart "system.cpu", context "system.cpu", family "cpu", dimension "system", value * 1 / 1 delta gives percentage (counter)
-netdata_system_cpu_total{chart="system.cpu",family="cpu",dimension="system"} 35084 1500066716438
-# COMMENT netdata_system_cpu_total: chart "system.cpu", context "system.cpu", family "cpu", dimension "nice", value * 1 / 1 delta gives percentage (counter)
-netdata_system_cpu_total{chart="system.cpu",family="cpu",dimension="nice"} 505 1500066716438
-# COMMENT netdata_system_cpu_total: chart "system.cpu", context "system.cpu", family "cpu", dimension "iowait", value * 1 / 1 delta gives percentage (counter)
-netdata_system_cpu_total{chart="system.cpu",family="cpu",dimension="iowait"} 23314 1500066716438
-# COMMENT netdata_system_cpu_total: chart "system.cpu", context "system.cpu", family "cpu", dimension "idle", value * 1 / 1 delta gives percentage (counter)
-netdata_system_cpu_total{chart="system.cpu",family="cpu",dimension="idle"} 918470 1500066716438
-```
-
-_(Netdata response for `system.cpu` with source=`as-collected`)_
-
-For more information check prometheus documentation.
-
-### Streaming data from upstream hosts
-
-The `format=prometheus` parameter only exports the host's Netdata metrics. If you are using the parent-child
-functionality of Netdata this ignores any upstream hosts - so you should consider using the below in your
-**prometheus.yml**:
-
-```yaml
-    metrics_path: '/api/v1/allmetrics'
-    params:
-      format: [prometheus_all_hosts]
-    honor_labels: true
-```
-
-This will report all upstream host data, and `honor_labels` will make Prometheus take note of the instance names
-provided.
-
-### Timestamps
-
-To pass the metrics through prometheus pushgateway, Netdata supports the option `&timestamps=no` to send the metrics
-without timestamps.
-
-## Netdata host variables
-
-Netdata collects various system configuration metrics, like the max number of TCP sockets supported, the max number of
-files allowed system-wide, various IPC sizes, etc. These metrics are not exposed to prometheus by default.
-
-To expose them, append `variables=yes` to the Netdata URL.
-
-### TYPE and HELP
-
-To save bandwidth, and because prometheus does not use them anyway, `# TYPE` and `# HELP` lines are suppressed. If
-wanted they can be re-enabled via `types=yes` and `help=yes`, e.g.
-`/api/v1/allmetrics?format=prometheus&types=yes&help=yes`
-
-Note that if enabled, the `# TYPE` and `# HELP` lines are repeated for every occurrence of a metric, which goes against the Prometheus documentation's [specification for these lines](https://github.com/prometheus/docs/blob/master/content/docs/instrumenting/exposition_formats.md#comments-help-text-and-type-information).
-
-### Names and IDs
-
-Netdata supports names and IDs for charts and dimensions. Usually IDs are unique identifiers as read by the system and
-names are human friendly labels (also unique).
-
-Most charts and metrics have the same ID and name, but in several cases they are different: disks with device-mapper,
-interrupts, QoS classes, statsd synthetic charts, etc.
-
-The default is controlled in `netdata.conf`:
-
-```conf
-[backend]
-	send names instead of ids = yes | no
-```
-
-You can overwrite it from prometheus, by appending to the URL:
-
--   `&names=no` to get IDs (the old behaviour)
--   `&names=yes` to get names
-
-### Filtering metrics sent to prometheus
-
-Netdata can filter the metrics it sends to prometheus with this setting:
-
-```conf
-[backend]
-	send charts matching = *
-```
-
-This settings accepts a space separated list of patterns to match the **charts** to be sent to prometheus. Each pattern
-can use `*` as wildcard, any number of times (e.g `*a*b*c*` is valid). Patterns starting with `!` give a negative match
-(e.g `!*.bad users.* groups.*` will send all the users and groups except `bad` user and `bad` group). The order is
-important: the first match (positive or negative) left to right, is used.
-
-### Changing the prefix of Netdata metrics
-
-Netdata sends all metrics prefixed with `netdata_`. You can change this in `netdata.conf`, like this:
-
-```conf
-[backend]
-	prefix = netdata
-```
-
-It can also be changed from the URL, by appending `&prefix=netdata`.
-
-### Metric Units
-
-The default source `average` adds the unit of measurement to the name of each metric (e.g. `_KiB_persec`). To hide the
-units and get the same metric names as with the other sources, append to the URL `&hideunits=yes`.
-
-The units were standardized in v1.12, with the effect of changing the metric names. To get the metric names as they were
-before v1.12, append to the URL `&oldunits=yes`
-
-### Accuracy of `average` and `sum` data sources
-
-When the data source is set to `average` or `sum`, Netdata remembers the last access of each client accessing prometheus
-metrics and uses this last access time to respond with the `average` or `sum` of all the entries in the database since
-that. This means that prometheus servers are not losing data when they access Netdata with data source = `average` or
-`sum`.
-
-To uniquely identify each prometheus server, Netdata uses the IP of the client accessing the metrics. If however the IP
-is not good enough for identifying a single prometheus server (e.g. when prometheus servers are accessing Netdata
-through a web proxy, or when multiple prometheus servers are NATed to a single IP), each prometheus may append
-`&server=NAME` to the URL. This `NAME` is used by Netdata to uniquely identify each prometheus server and keep track of
-its last access time.
-
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diff --git a/backends/prometheus/backend_prometheus.c b/backends/prometheus/backend_prometheus.c
deleted file mode 100644
index 1fb3fd42c..000000000
--- a/backends/prometheus/backend_prometheus.c
+++ /dev/null
@@ -1,797 +0,0 @@
-// SPDX-License-Identifier: GPL-3.0-or-later
-
-#define BACKENDS_INTERNALS
-#include "backend_prometheus.h"
-
-// ----------------------------------------------------------------------------
-// PROMETHEUS
-// /api/v1/allmetrics?format=prometheus and /api/v1/allmetrics?format=prometheus_all_hosts
-
-static struct prometheus_server {
-    const char *server;
-    uint32_t hash;
-    RRDHOST *host;
-    time_t last_access;
-    struct prometheus_server *next;
-} *prometheus_server_root = NULL;
-
-static inline time_t prometheus_server_last_access(const char *server, RRDHOST *host, time_t now) {
-    static netdata_mutex_t prometheus_server_root_mutex = NETDATA_MUTEX_INITIALIZER;
-
-    uint32_t hash = simple_hash(server);
-
-    netdata_mutex_lock(&prometheus_server_root_mutex);
-
-    struct prometheus_server *ps;
-    for(ps = prometheus_server_root; ps ;ps = ps->next) {
-        if (host == ps->host && hash == ps->hash && !strcmp(server, ps->server)) {
-            time_t last = ps->last_access;
-            ps->last_access = now;
-            netdata_mutex_unlock(&prometheus_server_root_mutex);
-            return last;
-        }
-    }
-
-    ps = callocz(1, sizeof(struct prometheus_server));
-    ps->server = strdupz(server);
-    ps->hash = hash;
-    ps->host = host;
-    ps->last_access = now;
-    ps->next = prometheus_server_root;
-    prometheus_server_root = ps;
-
-    netdata_mutex_unlock(&prometheus_server_root_mutex);
-    return 0;
-}
-
-static inline size_t backends_prometheus_name_copy(char *d, const char *s, size_t usable) {
-    size_t n;
-
-    for(n = 0; *s && n < usable ; d++, s++, n++) {
-        register char c = *s;
-
-        if(!isalnum(c)) *d = '_';
-        else *d = c;
-    }
-    *d = '\0';
-
-    return n;
-}
-
-static inline size_t backends_prometheus_label_copy(char *d, const char *s, size_t usable) {
-    size_t n;
-
-    // make sure we can escape one character without overflowing the buffer
-    usable--;
-
-    for(n = 0; *s && n < usable ; d++, s++, n++) {
-        register char c = *s;
-
-        if(unlikely(c == '"' || c == '\\' || c == '\n')) {
-            *d++ = '\\';
-            n++;
-        }
-        *d = c;
-    }
-    *d = '\0';
-
-    return n;
-}
-
-static inline char *backends_prometheus_units_copy(char *d, const char *s, size_t usable, int showoldunits) {
-    const char *sorig = s;
-    char *ret = d;
-    size_t n;
-
-    // Fix for issue 5227
-    if (unlikely(showoldunits)) {
-		static struct {
-			const char *newunit;
-			uint32_t hash;
-			const char *oldunit;
-		} units[] = {
-				  {"KiB/s", 0, "kilobytes/s"}
-				, {"MiB/s", 0, "MB/s"}
-				, {"GiB/s", 0, "GB/s"}
-				, {"KiB"  , 0, "KB"}
-				, {"MiB"  , 0, "MB"}
-				, {"GiB"  , 0, "GB"}
-				, {"inodes"       , 0, "Inodes"}
-				, {"percentage"   , 0, "percent"}
-				, {"faults/s"     , 0, "page faults/s"}
-				, {"KiB/operation", 0, "kilobytes per operation"}
-				, {"milliseconds/operation", 0, "ms per operation"}
-				, {NULL, 0, NULL}
-		};
-		static int initialized = 0;
-		int i;
-
-		if(unlikely(!initialized)) {
-			for (i = 0; units[i].newunit; i++)
-				units[i].hash = simple_hash(units[i].newunit);
-			initialized = 1;
-		}
-
-		uint32_t hash = simple_hash(s);
-		for(i = 0; units[i].newunit ; i++) {
-			if(unlikely(hash == units[i].hash && !strcmp(s, units[i].newunit))) {
-				// info("matched extension for filename '%s': '%s'", filename, last_dot);
-				s=units[i].oldunit;
-				sorig = s;
-				break;
-			}
-		}
-    }
-    *d++ = '_';
-    for(n = 1; *s && n < usable ; d++, s++, n++) {
-        register char c = *s;
-
-        if(!isalnum(c)) *d = '_';
-        else *d = c;
-    }
-
-    if(n == 2 && sorig[0] == '%') {
-        n = 0;
-        d = ret;
-        s = "_percent";
-        for( ; *s && n < usable ; n++) *d++ = *s++;
-    }
-    else if(n > 3 && sorig[n-3] == '/' && sorig[n-2] == 's') {
-        n = n - 2;
-        d -= 2;
-        s = "_persec";
-        for( ; *s && n < usable ; n++) *d++ = *s++;
-    }
-
-    *d = '\0';
-
-    return ret;
-}
-
-
-#define PROMETHEUS_ELEMENT_MAX 256
-#define PROMETHEUS_LABELS_MAX 1024
-#define PROMETHEUS_VARIABLE_MAX 256
-
-#define PROMETHEUS_LABELS_MAX_NUMBER 128
-
-struct host_variables_callback_options {
-    RRDHOST *host;
-    BUFFER *wb;
-    BACKEND_OPTIONS backend_options;
-    BACKENDS_PROMETHEUS_OUTPUT_OPTIONS output_options;
-    const char *prefix;
-    const char *labels;
-    time_t now;
-    int host_header_printed;
-    char name[PROMETHEUS_VARIABLE_MAX+1];
-};
-
-static int print_host_variables(RRDVAR *rv, void *data) {
-    struct host_variables_callback_options *opts = data;
-
-    if(rv->options & (RRDVAR_OPTION_CUSTOM_HOST_VAR|RRDVAR_OPTION_CUSTOM_CHART_VAR)) {
-        if(!opts->host_header_printed) {
-            opts->host_header_printed = 1;
-
-            if(opts->output_options & BACKENDS_PROMETHEUS_OUTPUT_HELP) {
-                buffer_sprintf(opts->wb, "\n# COMMENT global host and chart variables\n");
-            }
-        }
-
-        calculated_number value = rrdvar2number(rv);
-        if(isnan(value) || isinf(value)) {
-            if(opts->output_options & BACKENDS_PROMETHEUS_OUTPUT_HELP)
-                buffer_sprintf(opts->wb, "# COMMENT variable \"%s\" is %s. Skipped.\n", rv->name, (isnan(value))?"NAN":"INF");
-
-            return 0;
-        }
-
-        char *label_pre = "";
-        char *label_post = "";
-        if(opts->labels && *opts->labels) {
-            label_pre = "{";
-            label_post = "}";
-        }
-
-        backends_prometheus_name_copy(opts->name, rv->name, sizeof(opts->name));
-
-        if(opts->output_options & BACKENDS_PROMETHEUS_OUTPUT_TIMESTAMPS)
-            buffer_sprintf(opts->wb
-                           , "%s_%s%s%s%s " CALCULATED_NUMBER_FORMAT " %llu\n"
-                           , opts->prefix
-                           , opts->name
-                           , label_pre
-                           , opts->labels
-                           , label_post
-                           , value
-                           , opts->now * 1000ULL
-            );
-        else
-            buffer_sprintf(opts->wb, "%s_%s%s%s%s " CALCULATED_NUMBER_FORMAT "\n"
-                           , opts->prefix
-                           , opts->name
-                           , label_pre
-                           , opts->labels
-                           , label_post
-                           , value
-            );
-
-        return 1;
-    }
-
-    return 0;
-}
-
-static void rrd_stats_api_v1_charts_allmetrics_prometheus(RRDHOST *host, BUFFER *wb, const char *prefix, BACKEND_OPTIONS backend_options, time_t after, time_t before, int allhosts, BACKENDS_PROMETHEUS_OUTPUT_OPTIONS output_options) {
-    rrdhost_rdlock(host);
-
-    char hostname[PROMETHEUS_ELEMENT_MAX + 1];
-    backends_prometheus_label_copy(hostname, host->hostname, PROMETHEUS_ELEMENT_MAX);
-
-    char labels[PROMETHEUS_LABELS_MAX + 1] = "";
-    if(allhosts) {
-        if(output_options & BACKENDS_PROMETHEUS_OUTPUT_TIMESTAMPS)
-            buffer_sprintf(wb, "netdata_info{instance=\"%s\",application=\"%s\",version=\"%s\"} 1 %llu\n", hostname, host->program_name, host->program_version, now_realtime_usec() / USEC_PER_MS);
-        else
-            buffer_sprintf(wb, "netdata_info{instance=\"%s\",application=\"%s\",version=\"%s\"} 1\n", hostname, host->program_name, host->program_version);
-
-        if(host->tags && *(host->tags)) {
-            if(output_options & BACKENDS_PROMETHEUS_OUTPUT_TIMESTAMPS) {
-                buffer_sprintf(wb, "netdata_host_tags_info{instance=\"%s\",%s} 1 %llu\n", hostname, host->tags, now_realtime_usec() / USEC_PER_MS);
-
-                // deprecated, exists only for compatibility with older queries
-                buffer_sprintf(wb, "netdata_host_tags{instance=\"%s\",%s} 1 %llu\n", hostname, host->tags, now_realtime_usec() / USEC_PER_MS);
-            }
-            else {
-                buffer_sprintf(wb, "netdata_host_tags_info{instance=\"%s\",%s} 1\n", hostname, host->tags);
-
-                // deprecated, exists only for compatibility with older queries
-                buffer_sprintf(wb, "netdata_host_tags{instance=\"%s\",%s} 1\n", hostname, host->tags);
-            }
-
-        }
-
-        snprintfz(labels, PROMETHEUS_LABELS_MAX, ",instance=\"%s\"", hostname);
-    }
-    else {
-        if(output_options & BACKENDS_PROMETHEUS_OUTPUT_TIMESTAMPS)
-            buffer_sprintf(wb, "netdata_info{instance=\"%s\",application=\"%s\",version=\"%s\"} 1 %llu\n", hostname, host->program_name, host->program_version, now_realtime_usec() / USEC_PER_MS);
-        else
-            buffer_sprintf(wb, "netdata_info{instance=\"%s\",application=\"%s\",version=\"%s\"} 1\n", hostname, host->program_name, host->program_version);
-
-        if(host->tags && *(host->tags)) {
-            if(output_options & BACKENDS_PROMETHEUS_OUTPUT_TIMESTAMPS) {
-                buffer_sprintf(wb, "netdata_host_tags_info{%s} 1 %llu\n", host->tags, now_realtime_usec() / USEC_PER_MS);
-
-                // deprecated, exists only for compatibility with older queries
-                buffer_sprintf(wb, "netdata_host_tags{%s} 1 %llu\n", host->tags, now_realtime_usec() / USEC_PER_MS);
-            }
-            else {
-                buffer_sprintf(wb, "netdata_host_tags_info{%s} 1\n", host->tags);
-
-                // deprecated, exists only for compatibility with older queries
-                buffer_sprintf(wb, "netdata_host_tags{%s} 1\n", host->tags);
-            }
-        }
-    }
-
-    // send custom variables set for the host
-    if(output_options & BACKENDS_PROMETHEUS_OUTPUT_VARIABLES){
-        struct host_variables_callback_options opts = {
-                .host = host,
-                .wb = wb,
-                .labels = (labels[0] == ',')?&labels[1]:labels,
-                .backend_options = backend_options,
-                .output_options = output_options,
-                .prefix = prefix,
-                .now = now_realtime_sec(),
-                .host_header_printed = 0
-        };
-        foreach_host_variable_callback(host, print_host_variables, &opts);
-    }
-
-    // for each chart
-    RRDSET *st;
-    rrdset_foreach_read(st, host) {
-        char chart[PROMETHEUS_ELEMENT_MAX + 1];
-        char context[PROMETHEUS_ELEMENT_MAX + 1];
-        char family[PROMETHEUS_ELEMENT_MAX + 1];
-        char units[PROMETHEUS_ELEMENT_MAX + 1] = "";
-
-        backends_prometheus_label_copy(chart, (output_options & BACKENDS_PROMETHEUS_OUTPUT_NAMES && st->name)?st->name:st->id, PROMETHEUS_ELEMENT_MAX);
-        backends_prometheus_label_copy(family, st->family, PROMETHEUS_ELEMENT_MAX);
-        backends_prometheus_name_copy(context, st->context, PROMETHEUS_ELEMENT_MAX);
-
-        if(likely(backends_can_send_rrdset(backend_options, st))) {
-            rrdset_rdlock(st);
-
-            int as_collected = (BACKEND_OPTIONS_DATA_SOURCE(backend_options) == BACKEND_SOURCE_DATA_AS_COLLECTED);
-            int homogeneous = 1;
-            if(as_collected) {
-                if(rrdset_flag_check(st, RRDSET_FLAG_HOMOGENEOUS_CHECK))
-                    rrdset_update_heterogeneous_flag(st);
-
-                if(rrdset_flag_check(st, RRDSET_FLAG_HETEROGENEOUS))
-                    homogeneous = 0;
-            }
-            else {
-                if(BACKEND_OPTIONS_DATA_SOURCE(backend_options) == BACKEND_SOURCE_DATA_AVERAGE && !(output_options & BACKENDS_PROMETHEUS_OUTPUT_HIDEUNITS))
-                    backends_prometheus_units_copy(units, st->units, PROMETHEUS_ELEMENT_MAX, output_options & BACKENDS_PROMETHEUS_OUTPUT_OLDUNITS);
-            }
-
-            if(unlikely(output_options & BACKENDS_PROMETHEUS_OUTPUT_HELP))
-                buffer_sprintf(wb, "\n# COMMENT %s chart \"%s\", context \"%s\", family \"%s\", units \"%s\"\n"
-                               , (homogeneous)?"homogeneous":"heterogeneous"
-                               , (output_options & BACKENDS_PROMETHEUS_OUTPUT_NAMES && st->name) ? st->name : st->id
-                               , st->context
-                               , st->family
-                               , st->units
-                );
-
-            // for each dimension
-            RRDDIM *rd;
-            rrddim_foreach_read(rd, st) {
-                if(rd->collections_counter && !rrddim_flag_check(rd, RRDDIM_FLAG_OBSOLETE)) {
-                    char dimension[PROMETHEUS_ELEMENT_MAX + 1];
-                    char *suffix = "";
-
-                    if (as_collected) {
-                        // we need as-collected / raw data
-
-                        if(unlikely(rd->last_collected_time.tv_sec < after))
-                            continue;
-
-                        const char *t = "gauge", *h = "gives";
-                        if(rd->algorithm == RRD_ALGORITHM_INCREMENTAL ||
-                           rd->algorithm == RRD_ALGORITHM_PCENT_OVER_DIFF_TOTAL) {
-                            t = "counter";
-                            h = "delta gives";
-                            suffix = "_total";
-                        }
-
-                        if(homogeneous) {
-                            // all the dimensions of the chart, has the same algorithm, multiplier and divisor
-                            // we add all dimensions as labels
-
-                            backends_prometheus_label_copy(dimension, (output_options & BACKENDS_PROMETHEUS_OUTPUT_NAMES && rd->name) ? rd->name : rd->id, PROMETHEUS_ELEMENT_MAX);
-
-                            if(unlikely(output_options & BACKENDS_PROMETHEUS_OUTPUT_HELP))
-                                buffer_sprintf(wb
-                                               , "# COMMENT %s_%s%s: chart \"%s\", context \"%s\", family \"%s\", dimension \"%s\", value * " COLLECTED_NUMBER_FORMAT " / " COLLECTED_NUMBER_FORMAT " %s %s (%s)\n"
-                                               , prefix
-                                               , context
-                                               , suffix
-                                               , (output_options & BACKENDS_PROMETHEUS_OUTPUT_NAMES && st->name) ? st->name : st->id
-                                               , st->context
-                                               , st->family
-                                               , (output_options & BACKENDS_PROMETHEUS_OUTPUT_NAMES && rd->name) ? rd->name : rd->id
-                                               , rd->multiplier
-                                               , rd->divisor
-                                               , h
-                                               , st->units
-                                               , t
-                                );
-
-                            if(unlikely(output_options & BACKENDS_PROMETHEUS_OUTPUT_TYPES))
-                                buffer_sprintf(wb, "# TYPE %s_%s%s %s\n"
-                                               , prefix
-                                               , context
-                                               , suffix
-                                               , t
-                                );
-
-                            if(output_options & BACKENDS_PROMETHEUS_OUTPUT_TIMESTAMPS)
-                                buffer_sprintf(wb
-                                               , "%s_%s%s{chart=\"%s\",family=\"%s\",dimension=\"%s\"%s} " COLLECTED_NUMBER_FORMAT " %llu\n"
-                                               , prefix
-                                               , context
-                                               , suffix
-                                               , chart
-                                               , family
-                                               , dimension
-                                               , labels
-                                               , rd->last_collected_value
-                                               , timeval_msec(&rd->last_collected_time)
-                                );
-                            else
-                                buffer_sprintf(wb
-                                               , "%s_%s%s{chart=\"%s\",family=\"%s\",dimension=\"%s\"%s} " COLLECTED_NUMBER_FORMAT "\n"
-                                               , prefix
-                                               , context
-                                               , suffix
-                                               , chart
-                                               , family
-                                               , dimension
-                                               , labels
-                                               , rd->last_collected_value
-                                );
-                        }
-                        else {
-                            // the dimensions of the chart, do not have the same algorithm, multiplier or divisor
-                            // we create a metric per dimension
-
-                            backends_prometheus_name_copy(dimension, (output_options & BACKENDS_PROMETHEUS_OUTPUT_NAMES && rd->name) ? rd->name : rd->id, PROMETHEUS_ELEMENT_MAX);
-
-                            if(unlikely(output_options & BACKENDS_PROMETHEUS_OUTPUT_HELP))
-                                buffer_sprintf(wb
-                                               , "# COMMENT %s_%s_%s%s: chart \"%s\", context \"%s\", family \"%s\", dimension \"%s\", value * " COLLECTED_NUMBER_FORMAT " / " COLLECTED_NUMBER_FORMAT " %s %s (%s)\n"
-                                               , prefix
-                                               , context
-                                               , dimension
-                                               , suffix
-                                               , (output_options & BACKENDS_PROMETHEUS_OUTPUT_NAMES && st->name) ? st->name : st->id
-                                               , st->context
-                                               , st->family
-                                               , (output_options & BACKENDS_PROMETHEUS_OUTPUT_NAMES && rd->name) ? rd->name : rd->id
-                                               , rd->multiplier
-                                               , rd->divisor
-                                               , h
-                                               , st->units
-                                               , t
-                                );
-
-                            if(unlikely(output_options & BACKENDS_PROMETHEUS_OUTPUT_TYPES))
-                                buffer_sprintf(wb, "# TYPE %s_%s_%s%s %s\n"
-                                               , prefix
-                                               , context
-                                               , dimension
-                                               , suffix
-                                               , t
-                                );
-
-                            if(output_options & BACKENDS_PROMETHEUS_OUTPUT_TIMESTAMPS)
-                                buffer_sprintf(wb
-                                               , "%s_%s_%s%s{chart=\"%s\",family=\"%s\"%s} " COLLECTED_NUMBER_FORMAT " %llu\n"
-                                               , prefix
-                                               , context
-                                               , dimension
-                                               , suffix
-                                               , chart
-                                               , family
-                                               , labels
-                                               , rd->last_collected_value
-                                               , timeval_msec(&rd->last_collected_time)
-                                );
-                            else
-                                buffer_sprintf(wb
-                                               , "%s_%s_%s%s{chart=\"%s\",family=\"%s\"%s} " COLLECTED_NUMBER_FORMAT "\n"
-                                               , prefix
-                                               , context
-                                               , dimension
-                                               , suffix
-                                               , chart
-                                               , family
-                                               , labels
-                                               , rd->last_collected_value
-                                );
-                        }
-                    }
-                    else {
-                        // we need average or sum of the data
-
-                        time_t first_t = after, last_t = before;
-                        calculated_number value = backend_calculate_value_from_stored_data(st, rd, after, before, backend_options, &first_t, &last_t);
-
-                        if(!isnan(value) && !isinf(value)) {
-
-                            if(BACKEND_OPTIONS_DATA_SOURCE(backend_options) == BACKEND_SOURCE_DATA_AVERAGE)
-                                suffix = "_average";
-                            else if(BACKEND_OPTIONS_DATA_SOURCE(backend_options) == BACKEND_SOURCE_DATA_SUM)
-                                suffix = "_sum";
-
-                            backends_prometheus_label_copy(dimension, (output_options & BACKENDS_PROMETHEUS_OUTPUT_NAMES && rd->name) ? rd->name : rd->id, PROMETHEUS_ELEMENT_MAX);
-
-                            if (unlikely(output_options & BACKENDS_PROMETHEUS_OUTPUT_HELP))
-                                buffer_sprintf(wb, "# COMMENT %s_%s%s%s: dimension \"%s\", value is %s, gauge, dt %llu to %llu inclusive\n"
-                                               , prefix
-                                               , context
-                                               , units
-                                               , suffix
-                                               , (output_options & BACKENDS_PROMETHEUS_OUTPUT_NAMES && rd->name) ? rd->name : rd->id
-                                               , st->units
-                                               , (unsigned long long)first_t
-                                               , (unsigned long long)last_t
-                                );
-
-                            if (unlikely(output_options & BACKENDS_PROMETHEUS_OUTPUT_TYPES))
-                                buffer_sprintf(wb, "# TYPE %s_%s%s%s gauge\n"
-                                               , prefix
-                                               , context
-                                               , units
-                                               , suffix
-                                );
-
-                            if(output_options & BACKENDS_PROMETHEUS_OUTPUT_TIMESTAMPS)
-                                buffer_sprintf(wb, "%s_%s%s%s{chart=\"%s\",family=\"%s\",dimension=\"%s\"%s} " CALCULATED_NUMBER_FORMAT " %llu\n"
-                                               , prefix
-                                               , context
-                                               , units
-                                               , suffix
-                                               , chart
-                                               , family
-                                               , dimension
-                                               , labels
-                                               , value
-                                               , last_t * MSEC_PER_SEC
-                                );
-                            else
-                                buffer_sprintf(wb, "%s_%s%s%s{chart=\"%s\",family=\"%s\",dimension=\"%s\"%s} " CALCULATED_NUMBER_FORMAT "\n"
-                                               , prefix
-                                               , context
-                                               , units
-                                               , suffix
-                                               , chart
-                                               , family
-                                               , dimension
-                                               , labels
-                                               , value
-                                );
-                        }
-                    }
-                }
-            }
-
-            rrdset_unlock(st);
-        }
-    }
-
-    rrdhost_unlock(host);
-}
-
-#if ENABLE_PROMETHEUS_REMOTE_WRITE
-inline static void remote_write_split_words(char *str, char **words, int max_words) {
-    char *s = str;
-    int i = 0;
-
-    while(*s && i < max_words - 1) {
-        while(*s && isspace(*s)) s++; // skip spaces to the beginning of a tag name
-
-        if(*s)
-            words[i] = s;
-
-        while(*s && !isspace(*s) && *s != '=') s++; // find the end of the tag name
-
-        if(*s != '=') {
-            words[i] = NULL;
-            break;
-        }
-        *s = '\0';
-        s++;
-        i++;
-
-        while(*s && isspace(*s)) s++; // skip spaces to the beginning of a tag value
-
-        if(*s && *s == '"') s++; // strip an opening quote
-        if(*s)
-            words[i] = s;
-
-        while(*s && !isspace(*s) && *s != ',') s++; // find the end of the tag value
-
-        if(*s && *s != ',') {
-            words[i] = NULL;
-            break;
-        }
-        if(s != words[i] && *(s - 1) == '"') *(s - 1) = '\0'; // strip a closing quote
-        if(*s != '\0') {
-            *s = '\0';
-            s++;
-            i++;
-        }
-    }
-}
-
-void backends_rrd_stats_remote_write_allmetrics_prometheus(
-        RRDHOST *host
-        , const char *__hostname
-        , const char *prefix
-        , BACKEND_OPTIONS backend_options
-        , time_t after
-        , time_t before
-        , size_t *count_charts
-        , size_t *count_dims
-        , size_t *count_dims_skipped
-) {
-    char hostname[PROMETHEUS_ELEMENT_MAX + 1];
-    backends_prometheus_label_copy(hostname, __hostname, PROMETHEUS_ELEMENT_MAX);
-
-    backends_add_host_info("netdata_info", hostname, host->program_name, host->program_version, now_realtime_usec() / USEC_PER_MS);
-
-    if(host->tags && *(host->tags)) {
-        char tags[PROMETHEUS_LABELS_MAX + 1];
-        strncpy(tags, host->tags, PROMETHEUS_LABELS_MAX);
-        char *words[PROMETHEUS_LABELS_MAX_NUMBER] = {NULL};
-        int i;
-
-        remote_write_split_words(tags, words, PROMETHEUS_LABELS_MAX_NUMBER);
-
-        backends_add_host_info("netdata_host_tags_info", hostname, NULL, NULL, now_realtime_usec() / USEC_PER_MS);
-
-        for(i = 0; words[i] != NULL && words[i + 1] != NULL && (i + 1) < PROMETHEUS_LABELS_MAX_NUMBER; i += 2) {
-            backends_add_tag(words[i], words[i + 1]);
-        }
-    }
-
-    // for each chart
-    RRDSET *st;
-    rrdset_foreach_read(st, host) {
-        char chart[PROMETHEUS_ELEMENT_MAX + 1];
-        char context[PROMETHEUS_ELEMENT_MAX + 1];
-        char family[PROMETHEUS_ELEMENT_MAX + 1];
-        char units[PROMETHEUS_ELEMENT_MAX + 1] = "";
-
-        backends_prometheus_label_copy(chart, (backend_options & BACKEND_OPTION_SEND_NAMES && st->name)?st->name:st->id, PROMETHEUS_ELEMENT_MAX);
-        backends_prometheus_label_copy(family, st->family, PROMETHEUS_ELEMENT_MAX);
-        backends_prometheus_name_copy(context, st->context, PROMETHEUS_ELEMENT_MAX);
-
-        if(likely(backends_can_send_rrdset(backend_options, st))) {
-            rrdset_rdlock(st);
-
-            (*count_charts)++;
-
-            int as_collected = (BACKEND_OPTIONS_DATA_SOURCE(backend_options) == BACKEND_SOURCE_DATA_AS_COLLECTED);
-            int homogeneous = 1;
-            if(as_collected) {
-                if(rrdset_flag_check(st, RRDSET_FLAG_HOMOGENEOUS_CHECK))
-                    rrdset_update_heterogeneous_flag(st);
-
-                if(rrdset_flag_check(st, RRDSET_FLAG_HETEROGENEOUS))
-                    homogeneous = 0;
-            }
-            else {
-                if(BACKEND_OPTIONS_DATA_SOURCE(backend_options) == BACKEND_SOURCE_DATA_AVERAGE)
-                    backends_prometheus_units_copy(units, st->units, PROMETHEUS_ELEMENT_MAX, 0);
-            }
-
-            // for each dimension
-            RRDDIM *rd;
-            rrddim_foreach_read(rd, st) {
-                if(rd->collections_counter && !rrddim_flag_check(rd, RRDDIM_FLAG_OBSOLETE)) {
-                    char name[PROMETHEUS_LABELS_MAX + 1];
-                    char dimension[PROMETHEUS_ELEMENT_MAX + 1];
-                    char *suffix = "";
-
-                    if (as_collected) {
-                        // we need as-collected / raw data
-
-                        if(unlikely(rd->last_collected_time.tv_sec < after)) {
-                            debug(D_BACKEND, "BACKEND: not sending dimension '%s' of chart '%s' from host '%s', its last data collection (%lu) is not within our timeframe (%lu to %lu)", rd->id, st->id, __hostname, (unsigned long)rd->last_collected_time.tv_sec, (unsigned long)after, (unsigned long)before);
-                            (*count_dims_skipped)++;
-                            continue;
-                        }
-
-                        if(homogeneous) {
-                            // all the dimensions of the chart, has the same algorithm, multiplier and divisor
-                            // we add all dimensions as labels
-
-                            backends_prometheus_label_copy(dimension, (backend_options & BACKEND_OPTION_SEND_NAMES && rd->name) ? rd->name : rd->id, PROMETHEUS_ELEMENT_MAX);
-                            snprintf(name, PROMETHEUS_LABELS_MAX, "%s_%s%s", prefix, context, suffix);
-
-                            backends_add_metric(name, chart, family, dimension, hostname, rd->last_collected_value, timeval_msec(&rd->last_collected_time));
-                            (*count_dims)++;
-                        }
-                        else {
-                            // the dimensions of the chart, do not have the same algorithm, multiplier or divisor
-                            // we create a metric per dimension
-
-                            backends_prometheus_name_copy(dimension, (backend_options & BACKEND_OPTION_SEND_NAMES && rd->name) ? rd->name : rd->id, PROMETHEUS_ELEMENT_MAX);
-                            snprintf(name, PROMETHEUS_LABELS_MAX, "%s_%s_%s%s", prefix, context, dimension, suffix);
-
-                            backends_add_metric(name, chart, family, NULL, hostname, rd->last_collected_value, timeval_msec(&rd->last_collected_time));
-                            (*count_dims)++;
-                        }
-                    }
-                    else {
-                        // we need average or sum of the data
-
-                        time_t first_t = after, last_t = before;
-                        calculated_number value = backend_calculate_value_from_stored_data(st, rd, after, before, backend_options, &first_t, &last_t);
-
-                        if(!isnan(value) && !isinf(value)) {
-
-                            if(BACKEND_OPTIONS_DATA_SOURCE(backend_options) == BACKEND_SOURCE_DATA_AVERAGE)
-                                suffix = "_average";
-                            else if(BACKEND_OPTIONS_DATA_SOURCE(backend_options) == BACKEND_SOURCE_DATA_SUM)
-                                suffix = "_sum";
-
-                            backends_prometheus_label_copy(dimension, (backend_options & BACKEND_OPTION_SEND_NAMES && rd->name) ? rd->name : rd->id, PROMETHEUS_ELEMENT_MAX);
-                            snprintf(name, PROMETHEUS_LABELS_MAX, "%s_%s%s%s", prefix, context, units, suffix);
-
-                            backends_add_metric(name, chart, family, dimension, hostname, value, last_t * MSEC_PER_SEC);
-                            (*count_dims)++;
-                        }
-                    }
-                }
-            }
-
-            rrdset_unlock(st);
-        }
-    }
-}
-#endif /* ENABLE_PROMETHEUS_REMOTE_WRITE */
-
-static inline time_t prometheus_preparation(RRDHOST *host, BUFFER *wb, BACKEND_OPTIONS backend_options, const char *server, time_t now, BACKENDS_PROMETHEUS_OUTPUT_OPTIONS output_options) {
-    if(!server || !*server) server = "default";
-
-    time_t after  = prometheus_server_last_access(server, host, now);
-
-    int first_seen = 0;
-    if(!after) {
-        after = now - global_backend_update_every;
-        first_seen = 1;
-    }
-
-    if(after > now) {
-        // oops! this should never happen
-        after = now - global_backend_update_every;
-    }
-
-    if(output_options & BACKENDS_PROMETHEUS_OUTPUT_HELP) {
-        char *mode;
-        if(BACKEND_OPTIONS_DATA_SOURCE(backend_options) == BACKEND_SOURCE_DATA_AS_COLLECTED)
-            mode = "as collected";
-        else if(BACKEND_OPTIONS_DATA_SOURCE(backend_options) == BACKEND_SOURCE_DATA_AVERAGE)
-            mode = "average";
-        else if(BACKEND_OPTIONS_DATA_SOURCE(backend_options) == BACKEND_SOURCE_DATA_SUM)
-            mode = "sum";
-        else
-            mode = "unknown";
-
-        buffer_sprintf(wb, "# COMMENT netdata \"%s\" to %sprometheus \"%s\", source \"%s\", last seen %lu %s, time range %lu to %lu\n\n"
-                , host->hostname
-                , (first_seen)?"FIRST SEEN ":""
-                , server
-                , mode
-                , (unsigned long)((first_seen)?0:(now - after))
-                , (first_seen)?"never":"seconds ago"
-                , (unsigned long)after, (unsigned long)now
-        );
-    }
-
-    return after;
-}
-
-void backends_rrd_stats_api_v1_charts_allmetrics_prometheus_single_host(RRDHOST *host, BUFFER *wb, const char *server, const char *prefix, BACKEND_OPTIONS backend_options, BACKENDS_PROMETHEUS_OUTPUT_OPTIONS output_options) {
-    time_t before = now_realtime_sec();
-
-    // we start at the point we had stopped before
-    time_t after = prometheus_preparation(host, wb, backend_options, server, before, output_options);
-
-    rrd_stats_api_v1_charts_allmetrics_prometheus(host, wb, prefix, backend_options, after, before, 0, output_options);
-}
-
-void backends_rrd_stats_api_v1_charts_allmetrics_prometheus_all_hosts(RRDHOST *host, BUFFER *wb, const char *server, const char *prefix, BACKEND_OPTIONS backend_options, BACKENDS_PROMETHEUS_OUTPUT_OPTIONS output_options) {
-    time_t before = now_realtime_sec();
-
-    // we start at the point we had stopped before
-    time_t after = prometheus_preparation(host, wb, backend_options, server, before, output_options);
-
-    rrd_rdlock();
-    rrdhost_foreach_read(host) {
-        rrd_stats_api_v1_charts_allmetrics_prometheus(host, wb, prefix, backend_options, after, before, 1, output_options);
-    }
-    rrd_unlock();
-}
-
-#if ENABLE_PROMETHEUS_REMOTE_WRITE
-int backends_process_prometheus_remote_write_response(BUFFER *b) {
-    if(unlikely(!b)) return 1;
-
-    const char *s = buffer_tostring(b);
-    int len = buffer_strlen(b);
-
-    // do nothing with HTTP responses 200 or 204
-
-    while(!isspace(*s) && len) {
-        s++;
-        len--;
-    }
-    s++;
-    len--;
-
-    if(likely(len > 4 && (!strncmp(s, "200 ", 4) || !strncmp(s, "204 ", 4))))
-        return 0;
-    else
-        return discard_response(b, "prometheus remote write");
-}
-#endif
diff --git a/backends/prometheus/backend_prometheus.h b/backends/prometheus/backend_prometheus.h
deleted file mode 100644
index 8c14ddc26..000000000
--- a/backends/prometheus/backend_prometheus.h
+++ /dev/null
@@ -1,37 +0,0 @@
-// SPDX-License-Identifier: GPL-3.0-or-later
-
-#ifndef NETDATA_BACKEND_PROMETHEUS_H
-#define NETDATA_BACKEND_PROMETHEUS_H 1
-
-#include "backends/backends.h"
-
-typedef enum backends_prometheus_output_flags {
-    BACKENDS_PROMETHEUS_OUTPUT_NONE       = 0,
-    BACKENDS_PROMETHEUS_OUTPUT_HELP       = (1 << 0),
-    BACKENDS_PROMETHEUS_OUTPUT_TYPES      = (1 << 1),
-    BACKENDS_PROMETHEUS_OUTPUT_NAMES      = (1 << 2),
-    BACKENDS_PROMETHEUS_OUTPUT_TIMESTAMPS = (1 << 3),
-    BACKENDS_PROMETHEUS_OUTPUT_VARIABLES  = (1 << 4),
-    BACKENDS_PROMETHEUS_OUTPUT_OLDUNITS   = (1 << 5),
-    BACKENDS_PROMETHEUS_OUTPUT_HIDEUNITS  = (1 << 6)
-} BACKENDS_PROMETHEUS_OUTPUT_OPTIONS;
-
-extern void backends_rrd_stats_api_v1_charts_allmetrics_prometheus_single_host(RRDHOST *host, BUFFER *wb, const char *server, const char *prefix, BACKEND_OPTIONS backend_options, BACKENDS_PROMETHEUS_OUTPUT_OPTIONS output_options);
-extern void backends_rrd_stats_api_v1_charts_allmetrics_prometheus_all_hosts(RRDHOST *host, BUFFER *wb, const char *server, const char *prefix, BACKEND_OPTIONS backend_options, BACKENDS_PROMETHEUS_OUTPUT_OPTIONS output_options);
-
-#if ENABLE_PROMETHEUS_REMOTE_WRITE
-extern void backends_rrd_stats_remote_write_allmetrics_prometheus(
-        RRDHOST *host
-        , const char *__hostname
-        , const char *prefix
-        , BACKEND_OPTIONS backend_options
-        , time_t after
-        , time_t before
-        , size_t *count_charts
-        , size_t *count_dims
-        , size_t *count_dims_skipped
-);
-extern int backends_process_prometheus_remote_write_response(BUFFER *b);
-#endif
-
-#endif //NETDATA_BACKEND_PROMETHEUS_H
diff --git a/backends/prometheus/remote_write/Makefile.am b/backends/prometheus/remote_write/Makefile.am
deleted file mode 100644
index d049ef48c..000000000
--- a/backends/prometheus/remote_write/Makefile.am
+++ /dev/null
@@ -1,14 +0,0 @@
-# SPDX-License-Identifier: GPL-3.0-or-later
-
-AUTOMAKE_OPTIONS = subdir-objects
-MAINTAINERCLEANFILES = $(srcdir)/Makefile.in
-
-CLEANFILES = \
-    remote_write.pb.cc \
-    remote_write.pb.h \
-    $(NULL)
-
-dist_noinst_DATA = \
-    remote_write.proto \
-    README.md \
-    $(NULL)
diff --git a/backends/prometheus/remote_write/README.md b/backends/prometheus/remote_write/README.md
deleted file mode 100644
index b83575e10..000000000
--- a/backends/prometheus/remote_write/README.md
+++ /dev/null
@@ -1,41 +0,0 @@
-<!--
-title: "Prometheus remote write backend"
-custom_edit_url: https://github.com/netdata/netdata/edit/master/backends/prometheus/remote_write/README.md
--->
-
-# Prometheus remote write backend
-
-## Prerequisites
-
-To use the prometheus remote write API with [storage
-providers](https://prometheus.io/docs/operating/integrations/#remote-endpoints-and-storage)
-[protobuf](https://developers.google.com/protocol-buffers/) and [snappy](https://github.com/google/snappy) libraries
-should be installed first. Next, Netdata should be re-installed from the source. The installer will detect that the
-required libraries and utilities are now available.
-
-## Configuration
-
-An additional option in the backend configuration section is available for the remote write backend:
-
-```conf
-[backend]
-    remote write URL path = /receive
-```
-
-The default value is `/receive`. `remote write URL path` is used to set an endpoint path for the remote write protocol.
-For example, if your endpoint is `http://example.domain:example_port/storage/read` you should set
-
-```conf
-[backend]
-    destination = example.domain:example_port
-    remote write URL path = /storage/read
-```
-
-`buffered` and `lost` dimensions in the Netdata Backend Data Size operation monitoring chart estimate uncompressed
-buffer size on failures.
-
-## Notes
-
-The remote write backend does not support `buffer on failures`
-
-[![analytics](https://www.google-analytics.com/collect?v=1&aip=1&t=pageview&_s=1&ds=github&dr=https%3A%2F%2Fgithub.com%2Fnetdata%2Fnetdata&dl=https%3A%2F%2Fmy-netdata.io%2Fgithub%2Fbackends%2Fprometheus%2Fremote_write%2FREADME&_u=MAC~&cid=5792dfd7-8dc4-476b-af31-da2fdb9f93d2&tid=UA-64295674-3)](<>)
diff --git a/backends/prometheus/remote_write/remote_write.cc b/backends/prometheus/remote_write/remote_write.cc
deleted file mode 100644
index b919cffad..000000000
--- a/backends/prometheus/remote_write/remote_write.cc
+++ /dev/null
@@ -1,120 +0,0 @@
-// SPDX-License-Identifier: GPL-3.0-or-later
-
-#include <snappy.h>
-#include "exporting/prometheus/remote_write/remote_write.pb.h"
-#include "remote_write.h"
-
-using namespace prometheus;
-
-static google::protobuf::Arena arena;
-static WriteRequest *write_request;
-
-void backends_init_write_request() {
-    GOOGLE_PROTOBUF_VERIFY_VERSION;
-    write_request = google::protobuf::Arena::CreateMessage<WriteRequest>(&arena);
-}
-
-void backends_clear_write_request() {
-    write_request->clear_timeseries();
-}
-
-void backends_add_host_info(const char *name, const char *instance, const char *application, const char *version, const int64_t timestamp) {
-    TimeSeries *timeseries;
-    Sample *sample;
-    Label *label;
-
-    timeseries = write_request->add_timeseries();
-
-    label = timeseries->add_labels();
-    label->set_name("__name__");
-    label->set_value(name);
-
-    label = timeseries->add_labels();
-    label->set_name("instance");
-    label->set_value(instance);
-
-    if(application) {
-        label = timeseries->add_labels();
-        label->set_name("application");
-        label->set_value(application);
-    }
-
-    if(version) {
-        label = timeseries->add_labels();
-        label->set_name("version");
-        label->set_value(version);
-    }
-
-    sample = timeseries->add_samples();
-    sample->set_value(1);
-    sample->set_timestamp(timestamp);
-}
-
-// adds tag to the last created timeseries
-void backends_add_tag(char *tag, char *value) {
-    TimeSeries *timeseries;
-    Label *label;
-
-    timeseries = write_request->mutable_timeseries(write_request->timeseries_size() - 1);
-
-    label = timeseries->add_labels();
-    label->set_name(tag);
-    label->set_value(value);
-}
-
-void backends_add_metric(const char *name, const char *chart, const char *family, const char *dimension, const char *instance, const double value, const int64_t timestamp) {
-    TimeSeries *timeseries;
-    Sample *sample;
-    Label *label;
-
-    timeseries = write_request->add_timeseries();
-
-    label = timeseries->add_labels();
-    label->set_name("__name__");
-    label->set_value(name);
-
-    label = timeseries->add_labels();
-    label->set_name("chart");
-    label->set_value(chart);
-
-    label = timeseries->add_labels();
-    label->set_name("family");
-    label->set_value(family);
-
-    if(dimension) {
-        label = timeseries->add_labels();
-        label->set_name("dimension");
-        label->set_value(dimension);
-    }
-
-    label = timeseries->add_labels();
-    label->set_name("instance");
-    label->set_value(instance);
-
-    sample = timeseries->add_samples();
-    sample->set_value(value);
-    sample->set_timestamp(timestamp);
-}
-
-size_t backends_get_write_request_size(){
-#if GOOGLE_PROTOBUF_VERSION < 3001000
-    size_t size = (size_t)snappy::MaxCompressedLength(write_request->ByteSize());
-#else
-    size_t size = (size_t)snappy::MaxCompressedLength(write_request->ByteSizeLong());
-#endif
-
-    return (size < INT_MAX)?size:0;
-}
-
-int backends_pack_write_request(char *buffer, size_t *size) {
-    std::string uncompressed_write_request;
-    if(write_request->SerializeToString(&uncompressed_write_request) == false) return 1;
-
-    snappy::RawCompress(uncompressed_write_request.data(), uncompressed_write_request.size(), buffer, size);
-
-    return 0;
-}
-
-void backends_protocol_buffers_shutdown() {
-    google::protobuf::ShutdownProtobufLibrary();
-}
diff --git a/backends/prometheus/remote_write/remote_write.h b/backends/prometheus/remote_write/remote_write.h
deleted file mode 100644
index 1307d7281..000000000
--- a/backends/prometheus/remote_write/remote_write.h
+++ /dev/null
@@ -1,30 +0,0 @@
-// SPDX-License-Identifier: GPL-3.0-or-later
-
-#ifndef NETDATA_BACKEND_PROMETHEUS_REMOTE_WRITE_H
-#define NETDATA_BACKEND_PROMETHEUS_REMOTE_WRITE_H
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-void backends_init_write_request();
-
-void backends_clear_write_request();
-
-void backends_add_host_info(const char *name, const char *instance, const char *application, const char *version, const int64_t timestamp);
-
-void backends_add_tag(char *tag, char *value);
-
-void backends_add_metric(const char *name, const char *chart, const char *family, const char *dimension, const char *instance, const double value, const int64_t timestamp);
-
-size_t backends_get_write_request_size();
-
-int backends_pack_write_request(char *buffer, size_t *size);
-
-void backends_protocol_buffers_shutdown();
-
-#ifdef __cplusplus
-}
-#endif
-
-#endif //NETDATA_BACKEND_PROMETHEUS_REMOTE_WRITE_H
diff --git a/backends/prometheus/remote_write/remote_write.proto b/backends/prometheus/remote_write/remote_write.proto
deleted file mode 100644
index dfde254e1..000000000
--- a/backends/prometheus/remote_write/remote_write.proto
+++ /dev/null
@@ -1,29 +0,0 @@
-syntax = "proto3";
-package prometheus;
-
-option cc_enable_arenas = true;
-
-import "google/protobuf/descriptor.proto";
-
-message WriteRequest {
-  repeated TimeSeries timeseries = 1 [(nullable) = false];
-}
-
-message TimeSeries {
-  repeated Label labels   = 1 [(nullable) = false];
-  repeated Sample samples = 2 [(nullable) = false];
-}
-
-message Label {
-  string name  = 1;
-  string value = 2;
-}
-
-message Sample {
-  double value    = 1;
-  int64 timestamp = 2;
-}
-
-extend google.protobuf.FieldOptions {
-    bool nullable = 65001;
-}