Support configuring affinity

.sync.yml

@@ -13,6 +13,7 @@ docs/antora.yml:
     entries:
       - defaults
       - no_container_limits
+      - affinity
 
 Makefile:
   includes:

Makefile.additional.mk

@@ -7,3 +7,8 @@ test-nolimits: test
 .PHONY: test-default
 test-default: instance = defaults
 test-default: test
+
+.PHONY: test-affinity
+test-affinity: instance = affinity
+test-affinity: test
+

class/defaults.yml

@@ -16,6 +16,7 @@ parameters:
     service_pwd: ?{vaultkv:${customer:name}/${cluster:name}/${_instance}/service_pwd}
     monitor_pwd: ?{vaultkv:${customer:name}/${cluster:name}/${_instance}/monitor_pwd}
     replicas: 2
+    affinity: {}
     images:
       maxscale:
         image: ghcr.io/appuio/maxscale-docker

component/main.jsonnet

@@ -60,6 +60,7 @@ local deployment = kube.Deployment('maxscale') {
     replicas: params.replicas,
     template+: {
       spec+: {
+        affinity: params.affinity,
         containers_+: {
           maxscale: kube.Container('maxscale') {
             image: params.images.maxscale.image + ':' + params.images.maxscale.tag,

docs/modules/ROOT/pages/references/parameters.adoc

@@ -90,6 +90,27 @@ default:: `?{vaultkv:${customer:name}/${cluster:name}/maxscale/service_pwd}`
 type:: string
 default:: `?{vaultkv:${customer:name}/${cluster:name}/maxscale/monitor_pwd}`
 
+= Pod Affinity Parameters
+
+By default, `affinity` is set to `{}` so the pods get no specific affinity. You can override this freely to [choose any pod affinity rules](https://kubernetes.io/docs/concepts/scheduling-eviction/assign-pod-node/).
+
+[horizontal]
+type:: hash
+default:: `{}`
+
+```yaml
+parameters:
+  maxscale:
+    affinity:
+      nodeAffinity:
+        requiredDuringSchedulingIgnoredDuringExecution:
+          nodeSelectorTerms:
+          - matchExpressions:
+            - key: node-role.kubernetes.io/controlplane
+              operator: In
+              values:
+              - "false"
+```
 
 = Container Resource Parameters
 

tests/affinity.yml

@@ -0,0 +1,38 @@
+# Overwrite parameters here
+
+# parameters: {...}
+---
+parameters:
+  _instance: maxscale
+  facts:
+    distribution: openshift4
+  maxscale:
+    affinity:
+      nodeAffinity:
+        requiredDuringSchedulingIgnoredDuringExecution:
+          nodeSelectorTerms:
+            - matchExpressions:
+                - key: node-role.kubernetes.io/controlplane
+                  operator: In
+                  values:
+                    - "false"
+    namespace: maxscale-test
+    master_only_listen_address: 127.0.0.1
+    read_write_listen_address: 127.0.0.1
+    db1_address: db1.mygalera.test.example.org
+    db1_port: 3307
+    db2_address: db2.mygalera.test.example.org
+    db2_port: 3307
+    db3_address: db3.mygalera.test.example.org
+    db3_port: 3307
+    service_user: maxscale-testservice
+    monitor_user: maxscale-testmonitor
+    service_pwd: ?{vaultkv:${customer:name}/${cluster:name}/${_instance}/service_pwd}
+    monitor_pwd: ?{vaultkv:${customer:name}/${cluster:name}/${_instance}/monitor_pwd}
+    resources:
+      limits:
+        memory: 512Mi
+        cpu: 1234m
+      requests:
+        memory: 1024Mi
+        cpu: 123m