Adding upstream version 1.29.3.upstream/1.29.3upstream

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

9 files changed, 1537 insertions, 0 deletions

diff --git a/backends/prometheus/Makefile.am b/backends/prometheus/Makefile.am
new file mode 100644
index 0000000..334fca8
--- /dev/null
+++ b/backends/prometheus/Makefile.am
@@ -0,0 +1,12 @@
+# 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
new file mode 100644
index 0000000..10275fa
--- /dev/null
+++ b/backends/prometheus/README.md
@@ -0,0 +1,457 @@
+<!--
+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]
+      #
+      # sources: 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: avg(rate(netdata_cpu_cpu_percentage_average{dimension="idle"}[1m])) 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.
+
+[![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%2FREADME&_u=MAC~&cid=5792dfd7-8dc4-476b-af31-da2fdb9f93d2&tid=UA-64295674-3)](<>)
diff --git a/backends/prometheus/backend_prometheus.c b/backends/prometheus/backend_prometheus.c
new file mode 100644
index 0000000..a3ecf16
--- /dev/null
+++ b/backends/prometheus/backend_prometheus.c
@@ -0,0 +1,797 @@
+// 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 begining 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 begining 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
new file mode 100644
index 0000000..8c14ddc
--- /dev/null
+++ b/backends/prometheus/backend_prometheus.h
@@ -0,0 +1,37 @@
+// 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
new file mode 100644
index 0000000..d049ef4
--- /dev/null
+++ b/backends/prometheus/remote_write/Makefile.am
@@ -0,0 +1,14 @@
+# 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
new file mode 100644
index 0000000..b83575e
--- /dev/null
+++ b/backends/prometheus/remote_write/README.md
@@ -0,0 +1,41 @@
+<!--
+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
new file mode 100644
index 0000000..9448595
--- /dev/null
+++ b/backends/prometheus/remote_write/remote_write.cc
@@ -0,0 +1,120 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include <snappy.h>
+#include "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
new file mode 100644
index 0000000..1307d72
--- /dev/null
+++ b/backends/prometheus/remote_write/remote_write.h
@@ -0,0 +1,30 @@
+// 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
new file mode 100644
index 0000000..dfde254
--- /dev/null
+++ b/backends/prometheus/remote_write/remote_write.proto
@@ -0,0 +1,29 @@
+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;
+}