Openshift中的JCS集群

Question

我正在尝试设置部署在Openshift集群上的JCS分布式缓存(根据FT的最佳实践，有3个节点)。这3个缓存实例中的任何一个都可以接收一个事件，并且通过TCP连接将该事件分发给其他实例(以同步状态)。JCS的配置如下(假设集群中有3个节点A、B、C)

• jcs.auxiliary.attributes.TcpListenerPort=Node-A-Host:2001 ( TcpListenerPort -> )是Node-A中接收缓存事件的本地端口。相应的配置将出现在其他节点中，如，

- jcs.auxiliary.attributes.TcpListenerPort=Node-B-Host:2002 - jcs.auxiliary.attributes.TcpListenerPort=Node-C-Host:2003

)

• jcs.auxiliary.attributes.TcpServers=Node-B-Host:2002，Node:2003 (TcpServers ->是接收实例将缓存事件分发给

的列表)

我现在面临的问题是，

• 当我们在Openshift中部署应用程序时，我们不知道豆荚(缓存实例)将在哪个节点上。这使我无法为缓存实例配置TCP参数.

。

只是想知道在Openshift/K8s平台上是否有可靠的方法来解决这个问题。谢谢。

Answer 1

你在找StatefulSet。

现在无法设置tcpServers列表的原因是Pods主机名是不可预测的，当Deployments、ReplicaSets、.

考虑以下示例：

---
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: openldap-kube
  namespace: ci
spec:
  podManagementPolicy: OrderedReady
  replicas: 3
  selector:
    matchLabels:
      name: openldap-kube
  serviceName: openldap-kube
  template:
    metadata:
      labels:
        name: openldap-kube
    spec:
      affinity:
        podAntiAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
          - labelSelector:
              matchExpressions:
              - key: name
                operator: In
                values:
                - openldap-kube
            topologyKey: kubernetes.io/hostname
      containers:
      [ ... ]
        volumeMounts:
        - mountPath: /etc/ldap
          name: data
          subPath: config
        - mountPath: /var/lib/ldap
          name: data
          subPath: db
        - mountPath: /run
          name: run
      volumes:
      - emptyDir: {}
        name: run
  updateStrategy:
    type: RollingUpdate
  volumeClaimTemplates:
  - apiVersion: v1
    kind: PersistentVolumeClaim
    metadata:
      name: data
    spec:
      accessModes:
      - ReadWriteOnce
      resources:
        requests:
          storage: 8Gi
---
apiVersion: v1
kind: Service
metadata:
  name: openldap-kube
  namespace: ci
spec:
  clusterIP: None
  ports:
  - name: tcp-1389
    port: 1389
  - name: tcp-1636
    port: 1636
  selector:
    name: openldap-kube
  type: ClusterIP

在这种情况下(StatefulSet，带有spec.serviceName，Service有spec.type=ClusterIP和spec.clusterIP=None)，每个Pod都会有自己的DNS记录。命名了我的服务openldap-kube，命名空间ci后，可以在SDN中获得以下DNS记录：

$ getent hosts openldap-kube-0.openldap-kube.ci.svc.cluster.local
10.233.99.125   openldap-kube-0.openldap-kube.ci.svc.cluster.local
$ getent hosts openldap-kube-1.openldap-kube.ci.svc.cluster.local
10.233.114.206  openldap-kube-1.openldap-kube.ci.svc.cluster.local openldap-kube-1
$ getent hosts openldap-kube.ci.svc.cluster.local
10.233.114.206  openldap-kube.ci.svc.cluster.local
10.233.99.125   openldap-kube.ci.svc.cluster.local
$ getent hosts openldap-kube                     
10.233.114.206  openldap-kube.ci.svc.cluster.local
10.233.99.125   openldap-kube.ci.svc.cluster.local
$ getent hosts openldap-kube-1.openldap-kube
10.233.114.206  openldap-kube-1.openldap-kube.ci.svc.cluster.local

关于一些详尽无遗的样本，请参见：

https://gitlab.com/synacksynack/opsperator/docker-openldap/-/tree/master/deploy/kubernetes https://gitlab.com/synacksynack/opsperator/docker-percona/-/tree/master/deploy/kubernetes https://gitlab.com/synacksynack/opsperator/docker-mongodb/-/tree/master/deploy/kubernetes