fix: use flag to enable Prometheus (#12345)

docs/admin/provisioners.md

@@ -229,3 +229,17 @@ This can be disabled with a server-wide
 ```shell
 coder server --provisioner-daemons=0
 ```
+
+## Prometheus metrics
+
+Coder provisioner daemon exports metrics via the HTTP endpoint, which can be
+enabled using either the environment variable `CODER_PROMETHEUS_ENABLE` or the
+flag `--prometheus-enable`.
+
+The Prometheus endpoint address is `http://localhost:2112/` by default. You can
+use either the environment variable `CODER_PROMETHEUS_ADDRESS` or the flag
+`--prometheus-address <network-interface>:<port>` to select a different listen
+address.
+
+If you have provisioners daemons deployed as pods, it is advised to monitor them
+separately.

docs/admin/workspace-proxies.md

@@ -184,3 +184,14 @@ goes offline, the session will fall back to the primary proxy. This could take
 up to 60 seconds.
 
 ![Workspace proxy picker](../images/admin/workspace-proxy-picker.png)
+
+## Step 3: Observability
+
+Coder workspace proxy exports metrics via the HTTP endpoint, which can be
+enabled using either the environment variable `CODER_PROMETHEUS_ENABLE` or the
+flag `--prometheus-enable`.
+
+The Prometheus endpoint address is `http://localhost:2112/` by default. You can
+use either the environment variable `CODER_PROMETHEUS_ADDRESS` or the flag
+`--prometheus-address <network-interface>:<port>` to select a different listen
+address.

docs/cli/provisionerd_start.md

@@ -98,6 +98,16 @@ Deprecated and ignored.
 
 The bind address to serve prometheus metrics.
 
+### --prometheus-enable
+
+|             |                                       |
+| ----------- | ------------------------------------- |
+| Type        | <code>bool</code>                     |
+| Environment | <code>$CODER_PROMETHEUS_ENABLE</code> |
+| Default     | <code>false</code>                    |
+
+Serve prometheus metrics on the address defined by prometheus address.
+
 ### --psk
 
 |             |                                            |