Add recommended affinity setting for tidb and pump in note (#1251)

* Update values.yaml

* Update values.yaml

* Update values.yaml

charts/tidb-cluster/values.yaml

@@ -327,6 +327,29 @@ tidb:
   ## please read the affinity document before set your scheduling rule:
   ## ref: https://kubernetes.io/docs/concepts/configuration/assign-pod-node/#affinity-and-anti-affinity
   affinity: {}
+  ## If binlog.pump is enabled, the following affinity is recommended to make tidb and pump deploy at the same node in production
+  ## to avoid losing binlog in tidb if there was network partition error.
+  #  podAffinity:
+  #    requiredDuringSchedulingIgnoredDuringExecution:
+  #      - labelSelector:
+  #          matchExpressions:
+  #            - key: "app.kubernetes.io/component"
+  #              operator: In
+  #              values:
+  #                - "pump"
+  #            - key: "app.kubernetes.io/managed-by"
+  #              operator: In
+  #              values:
+  #                - "tidb-operator"
+  #            - key: "app.kubernetes.io/name"
+  #              operator: In
+  #              values:
+  #                - "tidb-cluster"
+  #            - key: "app.kubernetes.io/instance"
+  #              operator: In
+  #              values:
+  #                - <release-name>
+  #        topologyKey: kubernetes.io/hostname
 
   ## nodeSelector ensure pods only assigning to nodes which have each of the indicated key-value pairs as labels
   ## ref:https://kubernetes.io/docs/concepts/configuration/assign-pod-node/#nodeselector
@@ -511,6 +534,32 @@ binlog:
     # affinity for pump pod assignment, default: empty
     # ref: https://kubernetes.io/docs/concepts/configuration/assign-pod-node/#affinity-and-anti-affinity
     affinity: {}
+    ## The following setting is recommended to make each pump instance be distributed deployed in each node
+    ## Each node is recommended at most have one pump instance deployed.
+    #  podAntiAffinity:
+    #    preferredDuringSchedulingIgnoredDuringExecution:
+    #      - weight: 100
+    #        podAffinityTerm:
+    #          labelSelector:
+    #            matchExpressions:
+    #              - key: "app.kubernetes.io/component"
+    #                operator: In
+    #                values:
+    #                  - "pump"
+    #              - key: "app.kubernetes.io/managed-by"
+    #                operator: In
+    #                values:
+    #                  - "tidb-operator"
+    #              - key: "app.kubernetes.io/name"
+    #                operator: In
+    #                values:
+    #                  - "tidb-cluster"
+    #              - key: "app.kubernetes.io/instance"
+    #                operator: In
+    #                values:
+    #                  - <release-name>
+    #          topologyKey: kubernetes.io/hostname
+
     # tolerations are applied to pods, and allow pods to schedule onto nodes with matching taints.
     # refer to https://kubernetes.io/docs/concepts/configuration/taint-and-toleration
     tolerations: []