Opt to enable linkerd proxy shutdown from lifecycle preStop

Added a new `linkerd` object to values & schema. If `enabled=true` &
`shutdownAfterCheckpoint=true`, then the STS pod's `lifecycle.preStop`
hook will be configured to issue a shutdown call to the local
linkerd-proxy.

This is entirely optional. If a deployment is not using linkerd, then
this option should be left in the default disabled state.

Author: thedodd

charts/timescaledb-single/Chart.yaml

@@ -4,7 +4,7 @@
 apiVersion: v1
 name: timescaledb-single
 description: 'TimescaleDB HA Deployment.'
-version: 0.33.2
+version: 0.34.0
 icon: https://cdn.iconscout.com/icon/free/png-256/timescaledb-1958407-1651618.png
 
 # appVersion specifies the version of the software, which can vary wildly,

charts/timescaledb-single/docs/admin-guide.md

@@ -36,6 +36,8 @@ The following table lists the configurable parameters of the TimescaleDB Helm ch
 | `image.pullPolicy`                | The pull policy                             | `IfNotPresent`                                      |
 | `image.repository`                | The image to pull                           | `timescale/timescaledb-ha`                       |
 | `image.tag`                       | The version of the image to pull            | `pg13-ts2.1-latest`
+| `linkerd.enabled`                 | Enabled limited linkerd support.            | `false`
+| `linkerd.shutdownAfterCheckpoint` | When `true`, configures the StatefulSet Pod's `lifecycle.preStop` to issue a shutdown call to the local linkerd-proxy sidecar after checkpointing is complete. | `false`
 | `service.primary.type`        | The service type to use for the primary service | `ClusterIP`                          |
 | `service.primary.port`        | The service port to use for the primary service | `5432`                               |
 | `service.primary.nodePort`    | The service nodePort to use for the primary service when `type` is `NodePort` | `null` |
@@ -373,7 +375,7 @@ bootstrapFromBackup:
 Restoring a different deployment using an existing deployment is possible, but can be dangerous,
 as at this point you may be having 2 deployments pointing to the same S3 bucket/path.
 Therefore, `bootstrapFromBackup.repo1-path` is required to be set.
- 
+
 If there are any other changes to be made, for example the bucket itself, you can create a secret containing that
 information, for example:
 

charts/timescaledb-single/scripts/prestop.sql

@@ -60,3 +60,7 @@ CHECKPOINT;
     SELECT 'We are a primary: Successfully invoked checkpoints, now issuing a switchover.';
     \! curl -s http://localhost:8008/switchover -XPOST -d '{"leader": "$(hostname)"}'
 \endif
+
+\if :linkerdShutdown
+    \! curl -s -m 5 -X POST http://localhost:4191/shutdown
+\endif

charts/timescaledb-single/templates/configmap-scripts.yaml

@@ -33,4 +33,3 @@ data:
     {{- .Files.Get "scripts/patroni_callback.sh" | nindent 4 }}
   lifecycle_preStop.sql: |-
     {{- .Files.Get "scripts/prestop.sql" | nindent 4 }}
-...

charts/timescaledb-single/templates/statefulset-timescaledb.yaml

@@ -113,6 +113,7 @@ spec:
               command:
               - psql
               - -X
+              - --set=linkerdShutdown="{{ if and .Values.linkerd.enabled .Values.linkerd.terminateAfterCheckpoint }}1{{else}}0{{end}}"
               - --file
               - "{{ template "scripts_dir" . }}/lifecycle_preStop.sql"
         # When reusing an already existing volume it sometimes happens that the permissions

charts/timescaledb-single/values.schema.json

@@ -226,6 +226,22 @@
       },
       "type": "object"
     },
+    "linkerd": {
+      "additionalProperties": false,
+      "properties": {
+        "enabled": {
+          "type": [
+            "boolean"
+          ]
+        },
+        "terminateAfterCheckpoint": {
+          "type": [
+            "boolean"
+          ]
+        }
+      },
+      "type": "object"
+    },
     "enabled": {
       "additionalProperties": true
     },
@@ -818,6 +834,7 @@
     "fullnameOverride",
     "image",
     "curlImage",
+    "linkerd",
     "networkPolicy",
     "nodeSelector",
     "patroni",

charts/timescaledb-single/values.schema.yaml

@@ -18,6 +18,7 @@ required:
   - fullnameOverride
   - image
   - curlImage
+  - linkerd
   - networkPolicy
   - nodeSelector
   - patroni
@@ -432,6 +433,14 @@ properties:
         type:
           - string
           - "null"
+  linkerd:
+    type: object
+    additionalProperties: false
+    properties:
+      enabled:
+        type: boolean
+      terminateAfterCheckpoint:
+        type: boolean
   env:
     type:
       - array

charts/timescaledb-single/values.yaml

@@ -597,3 +597,11 @@ debug:
   # This command will be executed *before* the main container starts. In the
   # example below, we can mimick a slow restore by sleeping for 5 minutes before starting
   execStartPre:  # sleep 300
+
+# Support for specific use cases when deploying with the linkerd service mesh.
+linkerd:
+  enabled: false
+  # As part of the statefulset pod's `lifecycle.preStop`, call the local linkerd sidecar
+  # to cleanly terminate the proxy. If this is not performed, then the proxy will remain
+  # alive unnecessarily, blocking pod termination for a period of time.
+  terminateAfterCheckpoint: true