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diff --git a/docs/metrics-storage-management/enable-streaming.md b/docs/metrics-storage-management/enable-streaming.md new file mode 100644 index 00000000..fcbb16c8 --- /dev/null +++ b/docs/metrics-storage-management/enable-streaming.md @@ -0,0 +1,228 @@ +# How metrics streaming works + +Each node running Netdata can stream the metrics it collects, in real time, to another node. Streaming allows you to +replicate metrics data across multiple nodes, or centralize all your metrics data into a single time-series database +(TSDB). + +When one node streams metrics to another, the node receiving metrics can visualize them on the dashboard, run health checks to +[trigger alerts](https://github.com/netdata/netdata/blob/master/docs/monitor/view-active-alerts.md) and +[send notifications](https://github.com/netdata/netdata/blob/master/docs/monitor/enable-notifications.md), and +[export](https://github.com/netdata/netdata/blob/master/docs/export/external-databases.md) all metrics to an external TSDB. When Netdata streams metrics to another +Netdata, the receiving one is able to perform everything a Netdata instance is capable of. + +Streaming lets you decide exactly how you want to store and maintain metrics data. While we believe Netdata's +[distributed architecture](https://github.com/netdata/netdata/blob/master/docs/store/distributed-data-architecture.md) is +ideal for speed and scale, streaming provides centralization options and high data availability. + +This document will get you started quickly with streaming. More advanced concepts and suggested production deployments +can be found in the [streaming and replication reference](https://github.com/netdata/netdata/blob/master/streaming/README.md). + +## Streaming basics + +There are three types of nodes in Netdata's streaming ecosystem. + +- **Parent**: A node, running Netdata, that receives streamed metric data. +- **Child**: A node, running Netdata, that streams metric data to one or more parent. +- **Proxy**: A node, running Netdata, that receives metric data from a child and "forwards" them on to a + separate parent node. + +Netdata uses API keys, which are just random GUIDs, to authorize the communication between child and parent nodes. We +recommend using `uuidgen` for generating API keys, which can then be used across any number of streaming connections. +Or, you can generate unique API keys for each parent-child relationship. + +Once the parent node authorizes the child's API key, the child can start streaming metrics. + +It's important to note that the streaming connection uses TCP, UDP, or Unix sockets, _not HTTP_. To proxy streaming +metrics, you need to use a proxy that tunnels [OSI layer 4-7 +traffic](https://en.wikipedia.org/wiki/OSI_model#Layer_4:_Transport_Layer) without interfering with it, such as +[SOCKS](https://en.wikipedia.org/wiki/SOCKS) or Nginx's +[TCP/UDP load balancing](https://docs.nginx.com/nginx/admin-guide/load-balancer/tcp-udp-load-balancer/). + +## Supported streaming configurations + +Netdata supports any combination of parent, child, and proxy nodes that you can imagine. Any node can act as both a +parent, child, or proxy at the same time, sending or receiving streaming metrics from any number of other nodes. + +Here are a few example streaming configurations: + +- **Headless collector**: + - Child `A`, _without_ a database or web dashboard, streams metrics to parent `B`. + - `A` metrics are only available via the local Agent dashboard for `B`. + - `B` generates alerts for `A`. +- **Replication**: + - Child `A`, _with_ a database and web dashboard, streams metrics to parent `B`. + - `A` metrics are available on both local Agent dashboards, and can be stored with the same or different metrics + retention policies. + - Both `A` and `B` generate alerts. +- **Proxy**: + - Child `A`, _with or without_ a database, sends metrics to proxy `C`, also _with or without_ a database. `C` sends + metrics to parent `B`. + - Any node with a database can generate alerts. + + + +### A basic parent child setup + + + +For a predictable number of non-ephemeral nodes, install a Netdata agent on each node and replicate its data to a +Netdata parent, preferrably on a management/admin node outside your production infrastructure. +There are two variations of the basic setup: + +- When your nodes have sufficient RAM and disk IO the Netdata agents on each node can run with the default + settings for data collection and retention. + +- When your nodes have severe RAM and disk IO limitations (e.g. Raspberry Pis), you should + [optimize the Netdata agent's performance](https://github.com/netdata/netdata/blob/master/docs/guides/configure/performance.md). + +[Secure your nodes](https://github.com/netdata/netdata/blob/master/docs/category-overview-pages/secure-nodes.md) to +protect them from the internet by making their UI accessible only via an nginx proxy, with potentially different subdomains +for the parent and even each child, if necessary. + +Both children and the parent are connected to the cloud, to enable infrastructure observability, +[without transferring the collected data](https://github.com/netdata/netdata/blob/master/docs/netdata-security.md). +Requests for data are always serverd by a connected Netdata agent. When both a child and a parent are connected, +the cloud will always select the parent to query the user requested data. + +### An advanced setup + + + +When the nodes are ephemeral, we recommend using two parents in an active-active setup, and having the children not store data at all. + +Both parents are configured on each child, so that if one is not available, they connect to the other. + +The children in this set up are not connected to Netdata Cloud at all, as high availability is achieved with the second parent. + +## Enable streaming between nodes + +The simplest streaming configuration is **replication**, in which a child node streams its metrics in real time to a +parent node, and both nodes retain metrics in their own databases. + +To configure replication, you need two nodes, each running Netdata. First you'll first enable streaming on your parent +node, then enable streaming on your child node. When you're finished, you'll be able to see the child node's metrics in +the parent node's dashboard, quickly switch between the two dashboards, and be able to serve +[alert notifications](https://github.com/netdata/netdata/blob/master/docs/monitor/enable-notifications.md) from either or both nodes. + +### Enable streaming on the parent node + +First, log onto the node that will act as the parent. + +Run `uuidgen` to create a new API key, which is a randomly-generated machine GUID the Netdata Agent uses to identify +itself while initiating a streaming connection. Copy that into a separate text file for later use. + +> Find out how to [install `uuidgen`](https://command-not-found.com/uuidgen) on your node if you don't already have it. + +Next, open `stream.conf` using [`edit-config`](https://github.com/netdata/netdata/blob/master/docs/configure/nodes.md#use-edit-config-to-edit-configuration-files) +from within the [Netdata config directory](https://github.com/netdata/netdata/blob/master/docs/configure/nodes.md#the-netdata-config-directory). + +```bash +cd /etc/netdata +sudo ./edit-config stream.conf +``` + +Scroll down to the section beginning with `[API_KEY]`. Paste the API key you generated earlier between the brackets, so +that it looks like the following: + +```conf +[11111111-2222-3333-4444-555555555555] +``` + +Set `enabled` to `yes`, and `default memory mode` to `dbengine`. Leave all the other settings as their defaults. A +simplified version of the configuration, minus the commented lines, looks like the following: + +```conf +[11111111-2222-3333-4444-555555555555] + enabled = yes + default memory mode = dbengine +``` + +Save the file and close it, then restart Netdata with `sudo systemctl restart netdata`, or the [appropriate +method](https://github.com/netdata/netdata/blob/master/docs/configure/start-stop-restart.md) for your system. + +### Enable streaming on the child node + +Connect to your child node with SSH. + +Open `stream.conf` again. Scroll down to the `[stream]` section and set `enabled` to `yes`. Paste the IP address of your +parent node at the end of the `destination` line, and paste the API key generated on the parent node onto the `api key` +line. + +Leave all the other settings as their defaults. A simplified version of the configuration, minus the commented lines, +looks like the following: + +```conf +[stream] + enabled = yes + destination = 203.0.113.0 + api key = 11111111-2222-3333-4444-555555555555 +``` + +Save the file and close it, then restart Netdata with `sudo systemctl restart netdata`, or the [appropriate +method](https://github.com/netdata/netdata/blob/master/docs/configure/start-stop-restart.md) for your system. + +### Enable TLS/SSL on streaming (optional) + +While encrypting the connection between your parent and child nodes is recommended for security, it's not required to +get started. If you're not interested in encryption, skip ahead to [view streamed +metrics](#view-streamed-metrics-in-netdatas-dashboard). + +In this example, we'll use self-signed certificates. + +On the **parent** node, use OpenSSL to create the key and certificate, then use `chown` to make the new files readable +by the `netdata` user. + +```bash +sudo openssl req -newkey rsa:2048 -nodes -sha512 -x509 -days 365 -keyout /etc/netdata/ssl/key.pem -out /etc/netdata/ssl/cert.pem +sudo chown netdata:netdata /etc/netdata/ssl/cert.pem /etc/netdata/ssl/key.pem +``` + +Next, enforce TLS/SSL on the web server. Open `netdata.conf`, scroll down to the `[web]` section, and look for the `bind +to` setting. Add `^SSL=force` to turn on TLS/SSL. See the [web server +reference](https://github.com/netdata/netdata/blob/master/web/server/README.md#enabling-tls-support) for other TLS/SSL options. + +```conf +[web] + bind to = *=dashboard|registry|badges|management|streaming|netdata.conf^SSL=force +``` + +Next, connect to the **child** node and open `stream.conf`. Add `:SSL` to the end of the existing `destination` setting +to connect to the parent using TLS/SSL. Uncomment the `ssl skip certificate verification` line to allow the use of +self-signed certificates. + +```conf +[stream] + enabled = yes + destination = 203.0.113.0:SSL + ssl skip certificate verification = yes + api key = 11111111-2222-3333-4444-555555555555 +``` + +Restart both the parent and child nodes with `sudo systemctl restart netdata`, or the [appropriate +method](https://github.com/netdata/netdata/blob/master/docs/configure/start-stop-restart.md) for your system, to stream encrypted metrics using TLS/SSL. + +### View streamed metrics in Netdata Cloud + +In Netdata Cloud you should now be able to see a new parent showing up in the Home tab under "Nodes by data replication". +The replication factor for the child node has now increased to 2, meaning that its data is now highly available. + +You don't need to do anything else, as the cloud will automatically prefer to fetch data about the child from the parent +and switch to querying the child only when the parent is unavailable, or for some reason doesn't have the requested +data (e.g. the connection between parent and the child is broken). + +### View streamed metrics in Netdata's dashboard + +At this point, the child node is streaming its metrics in real time to its parent. Open the local Agent dashboard for +the parent by navigating to `http://PARENT-NODE:19999` in your browser, replacing `PARENT-NODE` with its IP address or +hostname. + +This dashboard shows parent metrics. To see child metrics, open the left-hand sidebar with the hamburger icon + +in the top panel. Both nodes appear under the **Replicated Nodes** menu. Click on either of the links to switch between +separate parent and child dashboards. + + + +The child dashboard is also available directly at `http://PARENT-NODE:19999/host/CHILD-HOSTNAME`, which in this example +is `http://203.0.113.0:19999/host/netdata-child`. + |