Merge branch 'public-single-node' into pmm-6401-read-prometheus-data-files

docs/CHANGELOG.md

@@ -20,6 +20,7 @@ The following tip changes can be tested by building VictoriaMetrics components f
 **Update note 2:** [vmalert](https://docs.victoriametrics.com/vmalert.html): the `crlfEscape` [template function](https://docs.victoriametrics.com/vmalert.html#template-functions) becames obsolete starting from this release. It can be safely removed from alerting templates, since `\n` chars are properly escaped with other `*Escape` functions now. See [this](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3139) and [this](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/890) issue for details.
 
 
+* FEATURE: [VictoriaMetrics enterprise](https://docs.victoriametrics.com/enterprise.html): add support for automatic `vmstorage` nodes discovering and updating at `vmselect` and `vminsert`. See [these docs](https://docs.victoriametrics.com/Cluster-VictoriaMetrics.html#automatic-vmstorage-discovery).
 * FEATURE: [VictoriaMetric enterprise](https://docs.victoriametrics.com/enterprise.html): allow configuring multiple retentions for distinct sets of time series. See [these docs](https://docs.victoriametrics.com/#retention-filters), [this](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/143) and [this](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/289) feature request.
 * FEATURE: [VictoriaMetric cluster enterprise](https://docs.victoriametrics.com/enterprise.html): add support for multiple retentions for distinct tenants - see [these docs](https://docs.victoriametrics.com/Cluster-VictoriaMetrics.html#retention-filters) and [this](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/143) and [this](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/289) feature request.
 * FEATURE: allow limiting memory usage on a per-query basis with `-search.maxMemoryPerQuery` command-line flag. See [this feature request](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3203).

docs/Cluster-VictoriaMetrics.md

@@ -159,6 +159,9 @@ A minimal cluster must contain the following nodes:
 - a single `vminsert` node with `-storageNode=<vmstorage_host>`
 - a single `vmselect` node with `-storageNode=<vmstorage_host>`
 
+[Enterprise version of VictoriaMetrics](https://docs.victoriametrics.com/enterprise.html) supports automatic discoverying and updating of `vmstorage` nodes.
+See [these docs](#automatic-vmstorage-discovery) for details.
+
 It is recommended to run at least two nodes for each service for high availability purposes. In this case the cluster continues working when a single node is temporarily unavailable and the remaining nodes can handle the increased workload. The node may be temporarily unavailable when the underlying hardware breaks, during software upgrades, migration or other maintenance tasks.
 
 It is preferred to run many small `vmstorage` nodes over a few big `vmstorage` nodes, since this reduces the workload increase on the remaining `vmstorage` nodes when some of `vmstorage` nodes become temporarily unavailable.
@@ -199,6 +202,21 @@ Additionally, all the VictoriaMetrics components allow setting flag values via e
 - For repeating flags, an alternative syntax can be used by joining the different values into one using `,` as separator (for example `-storageNode <nodeA> -storageNode <nodeB>` will translate to `storageNode=<nodeA>,<nodeB>`)
 - It is possible setting prefix for environment vars with `-envflag.prefix`. For instance, if `-envflag.prefix=VM_`, then env vars must be prepended with `VM_`
 
+## Automatic vmstorage discovery
+
+[Entrprise version of VictoriaMetrics](https://docs.victoriametrics.com/enterprise.html) supports [dns+srv](https://en.wikipedia.org/wiki/SRV_record) names
+at `-storageNode` command-line flag passed to `vminsert` and `vmstorage`. In this case the provided `dns+srv` names are resolved
+into tcp addresses of `vmstorage` nodes to connect to. The list of discovered `vmstorage` nodes is automatically updated at `vminsert` and `vmstorage`
+when it changes behind the corresponding `dns+srv` names. The `dns+srv` names must be prefixed with `dns+srv:` prefix.
+
+It is possible passing multiple `dns+srv` names to `-storageNode` command-line flag. In this case all these names are resolved to tcp addresses of `vmstorage` nodes to connect to.
+For example, `-storageNode='dns+srv:vmstorage-hot' -storageNode='dns+srv:vmstorage-cold'` .
+
+It is OK to pass regular static `vmstorage` addresses together with `dns+srv` addresses at `-storageNode`. For example,
+`-storageNode=vmstorage1,vmstorage2 -storageNode='dns+srv:vmstorage-autodiscovery'`.
+
+The currently discovered `vmstorage` nodes can be [monitored](#monitoring) vith `vm_rpc_vmstorage_is_reachable` and `vm_rpc_vmstorage_is_read_only` metrics.
+
 ## mTLS protection
 
 By default `vminsert` and `vmselect` nodes use unencrypted connections to `vmstorage` nodes, since it is assumed that all the cluster components run in a protected environment. [Enterprise version of VictoriaMetrics](https://docs.victoriametrics.com/enterprise.html) provides optional support for [mTLS connections](https://en.wikipedia.org/wiki/Mutual_authentication#mTLS) between cluster components. Pass `-cluster.tls=true` command-line flag to `vminsert`, `vmselect` and `vmstorage` nodes in order to enable mTLS protection. Additionally, `vminsert`, `vmselect` and `vmstorage` must be configured with mTLS certificates via `-cluster.tlsCertFile`, `-cluster.tlsKeyFile` command-line options. These certificates are mutually verified when `vminsert` and `vmselect` dial `vmstorage`.
@@ -834,7 +852,7 @@ Below is the output for `/path/to/vminsert -help`:
   -sortLabels
      Whether to sort labels for incoming samples before writing them to storage. This may be needed for reducing memory usage at storage when the order of labels in incoming samples is random. For example, if m{k1="v1",k2="v2"} may be sent as m{k2="v2",k1="v1"}. Enabled sorting for labels can slow down ingestion performance a bit
   -storageNode array
-     Comma-separated addresses of vmstorage nodes; usage: -storageNode=vmstorage-host1,...,vmstorage-hostN
+     Comma-separated addresses of vmstorage nodes; usage: -storageNode=vmstorage-host1,...,vmstorage-hostN . Enterprise version of VictoriaMetrics supports automatic discovery of vmstorage addresses via dns+srv records. For example, -storageNode=dns+srv:vmstorage.addrs . See https://docs.victoriametrics.com/Cluster-VictoriaMetrics.html#automatic-vmstorage-discovery
      Supports an array of values separated by comma or specified via multiple flags.
   -tls
      Whether to enable TLS for incoming HTTP requests at -httpListenAddr (aka https). -tlsCertFile and -tlsKeyFile must be set if -tls is set
@@ -1043,7 +1061,7 @@ Below is the output for `/path/to/vmselect -help`:
      Comma-separated addresses of vmselect nodes; usage: -selectNode=vmselect-host1,...,vmselect-hostN
      Supports an array of values separated by comma or specified via multiple flags.
   -storageNode array
-     Comma-separated addresses of vmstorage nodes; usage: -storageNode=vmstorage-host1,...,vmstorage-hostN
+     Comma-separated addresses of vmstorage nodes; usage: -storageNode=vmstorage-host1,...,vmstorage-hostN . Enterprise version of VictoriaMetrics supports automatic discovery of vmstorage addresses via dns+srv records. For example, -storageNode=dns+srv:vmstorage.addrs .See https://docs.victoriametrics.com/Cluster-VictoriaMetrics.html#automatic-vmstorage-discovery
      Supports an array of values separated by comma or specified via multiple flags.
   -tls
      Whether to enable TLS for incoming HTTP requests at -httpListenAddr (aka https). -tlsCertFile and -tlsKeyFile must be set if -tls is set

docs/enterprise.md

@@ -32,6 +32,8 @@ plus the following additional features:
   and increasing performance for queries over historical data.
 - [Multiple retentions](https://docs.victoriametrics.com/#retention-filters) - this feature allows reducing storage costs
   by specifying different retentions to different datasets.
+- [Automatic discovery of vmstorage nodes](https://docs.victoriametrics.com/Cluster-VictoriaMetrics.html#automatic-vmstorage-discovery) -
+  this feature allows updating the list of `vmstorage` nodes at `vminsert` and `vmselect` without the need to restart these services.
 - [Graphite querying](https://docs.victoriametrics.com/#graphite-render-api-usage) - this feature allows seamless
   transition from Graphite to VictoriaMetrics without the need to modify queries at dashboards and alerts.
   VictoriaMetrics allows reducing infrastructure costs by more than 10x comparing to Graphite -