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diff --git a/backends/README.md b/backends/README.md new file mode 100644 index 00000000..b449f060 --- /dev/null +++ b/backends/README.md @@ -0,0 +1,199 @@ + +# Metrics Long Term Archiving + +netdata supports backends for archiving the metrics, or providing long term dashboards, +using Grafana or other tools, like this: + + + +Since netdata collects thousands of metrics per server per second, which would easily congest any backend +server when several netdata servers are sending data to it, netdata allows sending metrics at a lower +frequency, by resampling them. + +So, although netdata collects metrics every second, it can send to the backend servers averages or sums every +X seconds (though, it can send them per second if you need it to). + +## features + +1. Supported backends + + - **graphite** (`plaintext interface`, used by **Graphite**, **InfluxDB**, **KairosDB**, + **Blueflood**, **ElasticSearch** via logstash tcp input and the graphite codec, etc) + + metrics are sent to the backend server as `prefix.hostname.chart.dimension`. `prefix` is + configured below, `hostname` is the hostname of the machine (can also be configured). + + - **opentsdb** (`telnet interface`, used by **OpenTSDB**, **InfluxDB**, **KairosDB**, etc) + + metrics are sent to opentsdb as `prefix.chart.dimension` with tag `host=hostname`. + + - **json** document DBs + + metrics are sent to a document db, `JSON` formatted. + + - **prometheus** is described at [prometheus page](prometheus/) since it pulls data from netdata. + +2. Only one backend may be active at a time. + +3. Netdata can filter metrics (at the chart level), to send only a subset of the collected metrics. + +4. Three modes of operation (for all backends): + + - `as collected`: the latest collected value is sent to the backend. This means that if netdata + is configured to send data to the backend every 10 seconds, only 1 out of 10 values will appear + at the backend server. The values are sent exactly as collected, before any multipliers or + dividers applied and before any interpolation. This mode emulates other data collectors, + such as `collectd` or `telegraf`. + + - `average`: the average of the interpolated values shown on the netdata graphs is sent to the + backend. So, if netdata is configured to send data to the backend server every 10 seconds, + the average of the 10 values shown on the netdata charts will be used. **If you can't decide + which mode to use, use `average`.** + + - `sum` or `volume`: the sum of the interpolated values shown on the netdata graphs is sent to + the backend. So, if netdata is configured to send data to the backend every 10 seconds, the + sum of the 10 values shown on the netdata charts will be used. + +5. This code is smart enough, not to slow down netdata, independently of the speed of the backend server. + +## configuration + +In `/etc/netdata/netdata.conf` you should have something like this (if not download the latest version +of `netdata.conf` from your netdata): + +``` +[backend] + enabled = yes | no + type = graphite | opentsdb | json + host tags = list of TAG=VALUE + destination = space separated list of [PROTOCOL:]HOST[:PORT] - the first working will be used + data source = average | sum | as collected + prefix = netdata + hostname = my-name + update every = 10 + buffer on failures = 10 + timeout ms = 20000 + send charts matching = * + send hosts matching = localhost * + send names instead of ids = yes +``` + +- `enabled = yes | no`, enables or disables sending data to a backend + +- `type = graphite | opentsdb | json`, selects the backend type + +- `destination = host1 host2 host3 ...`, accepts **a space separated list** of hostnames, + IPs (IPv4 and IPv6) and ports to connect to. + Netdata will use the **first available** to send the metrics. + + The format of each item in this list, is: `[PROTOCOL:]IP[:PORT]`. + + `PROTOCOL` can be `udp` or `tcp`. `tcp` is the default and only supported by the current backends. + + `IP` can be `XX.XX.XX.XX` (IPv4), or `[XX:XX...XX:XX]` (IPv6). + For IPv6 you can to enclose the IP in `[]` to separate it from the port. + + `PORT` can be a number of a service name. If omitted, the default port for the backend will be used + (graphite = 2003, opentsdb = 4242). + + Example IPv4: + +``` + destination = 10.11.14.2:4242 10.11.14.3:4242 10.11.14.4:4242 +``` + + Example IPv6 and IPv4 together: + +``` + destination = [ffff:...:0001]:2003 10.11.12.1:2003 +``` + + When multiple servers are defined, netdata will try the next one when the first one fails. This allows + you to load-balance different servers: give your backend servers in different order on each netdata. + + netdata also ships [`nc-backend.sh`](nc-backend.sh), + a script that can be used as a fallback backend to save the metrics to disk and push them to the + time-series database when it becomes available again. It can also be used to monitor / trace / debug + the metrics netdata generates. + +- `data source = as collected`, or `data source = average`, or `data source = sum`, selects the kind of + data that will be sent to the backend. + +- `hostname = my-name`, is the hostname to be used for sending data to the backend server. By default + this is `[global].hostname`. + +- `prefix = netdata`, is the prefix to add to all metrics. + +- `update every = 10`, is the number of seconds between sending data to the backend. netdata will add + some randomness to this number, to prevent stressing the backend server when many netdata servers send + data to the same backend. This randomness does not affect the quality of the data, only the time they + are sent. + +- `buffer on failures = 10`, is the number of iterations (each iteration is `[backend].update every` seconds) + to buffer data, when the backend is not available. If the backend fails to receive the data after that + many failures, data loss on the backend is expected (netdata will also log it). + +- `timeout ms = 20000`, is the timeout in milliseconds to wait for the backend server to process the data. + By default this is `2 * update_every * 1000`. + +- `send hosts matching = localhost *` includes one or more space separated patterns, using ` * ` as wildcard + (any number of times within each pattern). The patterns are checked against the hostname (the localhost + is always checked as `localhost`), allowing us to filter which hosts will be sent to the backend when + this netdata is a central netdata aggregating multiple hosts. A pattern starting with ` ! ` gives a + negative match. So to match all hosts named `*db*` except hosts containing `*slave*`, use + `!*slave* *db*` (so, the order is important: the first pattern matching the hostname will be used - positive + or negative). + +- `send charts matching = *` includes one or more space separated patterns, using ` * ` as wildcard (any + number of times within each pattern). The patterns are checked against both chart id and chart name. + A pattern starting with ` ! ` gives a negative match. So to match all charts named `apps.*` + except charts ending in `*reads`, use `!*reads apps.*` (so, the order is important: the first pattern + matching the chart id or the chart name will be used - positive or negative). + +- `send names instead of ids = yes | no` controls the metric names netdata should send to backend. + 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. + +- `host tags = list of TAG=VALUE` defines tags that should be appended on all metrics for the given host. + These are currently only sent to opentsdb and prometheus. Please use the appropriate format for each + time-series db. For example opentsdb likes them like `TAG1=VALUE1 TAG2=VALUE2`, but prometheus like + `tag1="value1",tag2="value2"`. Host tags are mirrored with database replication (streaming of metrics + between netdata servers). + +## monitoring operation + +netdata provides 5 charts: + +1. **Buffered metrics**, the number of metrics netdata added to the buffer for dispatching them to the + backend server. + +2. **Buffered data size**, the amount of data (in KB) netdata added the buffer. + +3. ~~**Backend latency**, the time the backend server needed to process the data netdata sent. + If there was a re-connection involved, this includes the connection time.~~ + (this chart has been removed, because it only measures the time netdata needs to give the data + to the O/S - since the backend servers do not ack the reception, netdata does not have any means + to measure this properly). + +4. **Backend operations**, the number of operations performed by netdata. + +5. **Backend thread CPU usage**, the CPU resources consumed by the netdata thread, that is responsible + for sending the metrics to the backend server. + + + +## alarms + +The latest version of the alarms configuration for monitoring the backend is [here](../health/health.d/backend.conf) + +netdata adds 4 alarms: + +1. `backend_last_buffering`, number of seconds since the last successful buffering of backend data +2. `backend_metrics_sent`, percentage of metrics sent to the backend server +3. `backend_metrics_lost`, number of metrics lost due to repeating failures to contact the backend server +4. ~~`backend_slow`, the percentage of time between iterations needed by the backend time to process the data sent by netdata~~ (this was misleading and has been removed). + + + |