k8s采用StatefulSet部署redis三主三从集群并初始化集群
部署简介：
1. 控制器：采用StatefulSet进行redis的部署。它为了解决有状态服务的问题，它所管理的Pod拥有固定的Pod名称，启停顺序。
2. 服务发现：两个svc，一个是暴露对外（NodePort service），一个是StatefulSet部署使用（headless service）。
在StatefulSet中与之对应的headless service，headless service，即无头服务，与service的区别就是它没有Cluster IP，解析它的名称时将返回该Headless Service对应的全部Pod的Endpoint列表。
3. 存储：数据存储：nfs。使用nfs作为后端存储，创建pv,pvc达到redis data数据存储持久化；配置存储：configmaps。创建configmaps存储，存储redis.conf配置信息
4. redis镜像：直接在redis官网下载制作，目前redis官网引入了docker hub，也可以直接跳转到docker hub下载最新版本
开始部署：
一、下载redis镜像
redis官网：https://redis.io/download/
目前官网最新版本是7.0.5，跳转到docker hub，看到目前最新的镜像是7.0.4版本
docker hub上最新版本，这次部署就是用7.0.4版本镜像，直接在服务器上：docker pull redis:7.0.4
二、创建存储共享目录
部署好nfs后，在本地创建存储共享目录，pv1-6
[root@k8s-master1 ~]# cd /data/k8s/redis/
[root@k8s-master1 redis]# ll
total 0
drwxr-xr-x 3 root root 61 Sep 22 09:13 pv1
drwxr-xr-x 3 root root 61 Sep 22 09:13 pv2
drwxr-xr-x 3 root root 45 Sep 21 18:10 pv3
drwxr-xr-x 3 root root 61 Sep 22 09:40 pv4
drwxr-xr-x 3 root root 45 Sep 21 18:10 pv5
drwxr-xr-x 3 root root 61 Sep 22 09:13 pv6
三、创建pv
创建6个pv，用于存储redis data数据
[root@k8s-master1 redis]# cat redis-pv.yaml
apiVersion: v1
kind: PersistentVolume
metadata:
name: redis-pv1 #pv名称
labels:
type: sata #标记存储类型
namespace: my-ns-redis #所属命名空间
spec:
capacity: #存储能力
storage: 2Gi
accessModes:
- ReadWriteMany #可以被多节点多次读写
persistentVolumeReclaimPolicy: Retain #pvc删除后数据保留模式
storageClassName: "redis" #storageClass名称，使用nfs不需要单独传教storageClass，直接标记名称后续引用。nfs不支持动态pv
nfs: #nfs存储
path: "/data/k8s/redis/pv1" #共享目录，需要主机上真实存在
server: 192.168.198.144 #nfs地址
readOnly: false
---
apiVersion: v1
kind: PersistentVolume
metadata:
name: redis-pv2
labels:
type: sata
namespace: my-ns-redis
spec:
capacity:
storage: 2Gi
accessModes:
- ReadWriteMany
persistentVolumeReclaimPolicy: Retain
storageClassName: "redis"
nfs:
path: "/data/k8s/redis/pv2"
server: 192.168.198.144
readOnly: false
---
apiVersion: v1
kind: PersistentVolume
metadata:
name: redis-pv3
labels:
type: sata
namespace: my-ns-redis
spec:
capacity:
storage: 2Gi
accessModes:
- ReadWriteMany
persistentVolumeReclaimPolicy: Retain
storageClassName: "redis"
nfs:
path: "/data/k8s/redis/pv3"
server: 192.168.198.144
readOnly: false
---
apiVersion: v1
kind: PersistentVolume
metadata:
name: redis-pv4
labels:
type: sata
namespace: my-ns-redis
spec:
capacity:
storage: 2Gi
accessModes:
- ReadWriteMany
persistentVolumeReclaimPolicy: Retain
storageClassName: "redis"
nfs:
path: "/data/k8s/redis/pv4"
server: 192.168.198.144
readOnly: false
---
apiVersion: v1
kind: PersistentVolume
metadata:
name: redis-pv5
labels:
type: sata
namespace: my-ns-redis
spec:
capacity:
storage: 2Gi
accessModes:
- ReadWriteMany
persistentVolumeReclaimPolicy: Retain
storageClassName: "redis"
nfs:
path: "/data/k8s/redis/pv5"
server: 192.168.198.144
readOnly: false
---
apiVersion: v1
kind: PersistentVolume
metadata:
name: redis-pv6
labels:
type: sata
namespace: my-ns-redis
spec:
capacity:
storage: 2Gi
accessModes:
- ReadWriteMany
persistentVolumeReclaimPolicy: Retain
storageClassName: "redis"
nfs:
path: "/data/k8s/redis/pv6"
server: 192.168.198.144
readOnly: false
#使用yaml文件创建pv
[root@k8s-master1 redis]# kubectl create -f redis-pv.yaml
四、创建configmap
将Redis的配置文件转化为Configmap，这是一种更方便的配置读取方式。配置文件redis.conf如下
#redis配置，本地直接创建
[root@k8s-master1 redis]# cat redis.conf
appendonly yes
cluster-enabled yes
cluster-config-file /var/lib/redis/nodes.conf
cluster-node-timeout 5000
dir /var/lib/redis
port 6379
#创建configmap
[root@k8s-master1 redis]# kubectl create configmap redis-conf --from-file=redis.conf -n my-ns-redis
#查询configmap信息
[root@k8s-master1 redis]# kubectl get cm -n my-ns-redis
NAME DATA AGE
redis-conf 1 17h
[root@k8s-master1 redis]# kubectl describe cm -n my-ns-redis redis-conf
Name: redis-conf
Namespace: my-ns-redis
Labels: <none>
Annotations: <none>
Data
====
redis.conf:
----
appendonly yes
cluster-enabled yes
cluster-config-file /var/lib/redis/nodes.conf
cluster-node-timeout 5000
dir /var/lib/redis
port 6379
Events: <none>
五、创建headless service
Headless service是StatefulSet实现稳定网络标识的基础，我们需要提前创建
[root@k8s-master1 redis]# cat headless-service.yaml
apiVersion: v1
kind: Service
metadata:
name: redis-service
namespace: my-ns-redis
labels:
app: redis
spec:
ports:
- name: redis-port
port: 6379
clusterIP: None
selector:
app: redis
[root@k8s-master1 redis]# kubectl create -f headless-service.yaml
六、通过StatefulSet创建redis集群节点
通过StatefulSet创建6个redis的pod ，实现3主3从的redis集群
[root@k8s-master1 redis]# cat redis-sts.yaml
apiVersion: apps/v1
kind: StatefulSet #StatefulSet类型
metadata:
name: redis-app #StatefulSet名称
namespace: my-ns-redis #使用的命名空间
spec:
serviceName: "redis-service" #引用上面创建的headless service，名字必须一致
replicas: 6 #副本数
selector: #标签选择器
matchLabels:
app: redis #选择redis标签
appCluster: redis-cluster
template: #容器模板
metadata:
labels:
app: redis #容器标签：redis
appCluster: redis-cluster
spec:
containers:
- name: redis #容器名字
image: "redis:7.0.4" #使用的镜像
command: ["/bin/bash", "-ce", "tail -f /dev/null"]
command: ["redis-server"]
args:
- "/etc/redis/redis.conf"
- "--protected-mode"
- "no"
ports:
- name: redis
containerPort: 6379
protocol: "TCP"
- name: cluster
containerPort: 16379
protocol: "TCP"
volumeMounts: #挂载卷
- name: "redis-conf" #自定义挂载卷1的名称
mountPath: "/etc/redis" #挂载的路径，这个是redis容器里面的路径
- name: "redis-data" #自定义挂载卷2的名称
mountPath: "/var/lib/redis" #挂载的路径
volumes:
- name: "redis-conf" #引用挂载，名字要和上面自定义的一致，否则无法对应挂载
configMap: #使用的存储类型
name: "redis-conf" #引用之前创建的configMap存储，名字要和之前创建使用的名字一致
items: #可以不写
- key: "redis.conf"
path: "redis.conf" #这个就表示mountPath: "/etc/redis"+path: "redis.conf" ，最终：/etc/redis/redis.conf
volumeClaimTemplates: #创建pvc的模板，我们没有单独创建pvc，直接使用模板创建
- metadata:
name: redis-data #引用上面自定义的挂载卷2的名称，必须一致
spec: #元数据
accessModes: [ "ReadWriteMany" ] #必须和前面创建的pv的保持一致，否则pv，pvc可能绑定失败
storageClassName: "redis" #必须和前面创建的pv的保持一致
resources:
requests:
storage: 1Gi #需求的存储大小，小于等于pv的存储
#使用yaml文件创建
[root@k8s-master1 redis]# kubectl create -f redis-sts.yaml
#查询
[root@k8s-master1 redis]# kubectl get all -n my-ns-redis
NAME READY STATUS RESTARTS AGE
pod/redis-app-0 1/1 Running 0 64m
pod/redis-app-1 1/1 Running 1 16h
pod/redis-app-2 1/1 Running 1 16h
pod/redis-app-3 1/1 Running 1 16h
pod/redis-app-4 1/1 Running 1 16h
pod/redis-app-5 1/1 Running 1 16h
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/redis-service ClusterIP None <none> 6379/TCP 17h
NAME READY AGE
statefulset.apps/redis-app 6/6 16h
#pv,pvc均已成功绑定
[root@k8s-master1 redis]# kubectl get pv,pvc -n my-ns-redis
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE 6d18h
persistentvolume/redis-pv1 2Gi RWX Retain Bound my-ns-redis/redis-data-redis-app-3 redis 17h
persistentvolume/redis-pv2 2Gi RWX Retain Bound my-ns-redis/redis-data-redis-app-5 redis 17h
persistentvolume/redis-pv3 2Gi RWX Retain Bound my-ns-redis/redis-data-redis-app-2 redis 17h
persistentvolume/redis-pv4 2Gi RWX Retain Bound my-ns-redis/redis-data-redis-app-0 redis 17h
persistentvolume/redis-pv5 2Gi RWX Retain Bound my-ns-redis/redis-data-redis-app-1 redis 17h
persistentvolume/redis-pv6 2Gi RWX Retain Bound my-ns-redis/redis-data-redis-app-4 redis 17h
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
persistentvolumeclaim/redis-data-redis-app-0 Bound redis-pv4 2Gi RWX redis 16h
persistentvolumeclaim/redis-data-redis-app-1 Bound redis-pv5 2Gi RWX redis 16h
persistentvolumeclaim/redis-data-redis-app-2 Bound redis-pv3 2Gi RWX redis 16h
persistentvolumeclaim/redis-data-redis-app-3 Bound redis-pv1 2Gi RWX redis 16h
persistentvolumeclaim/redis-data-redis-app-4 Bound redis-pv6 2Gi RWX redis 16h
persistentvolumeclaim/redis-data-redis-app-5 Bound redis-pv2 2Gi RWX redis 16h
七、初始化集群
#进入其中一个容器
[root@k8s-master1 ~]# kubectl exec -it -n my-ns-redis redis-app-0 /bin/bash
kubectl exec [POD] [COMMAND] is DEPRECATED and will be removed in a future version. Use kubectl exec [POD] -- [COMMAND] instead.
root@redis-app-0:/data#
#查询集群信息，可以看到cluster_state:fail失败，cluster_known_nodes:1节点数只有一个
root@redis-app-0:/data# redis-cli -c
127.0.0.1:6379> CLUSTER INFO
cluster_state:fail
cluster_slots_assigned:0
cluster_slots_ok:0
cluster_slots_pfail:0
cluster_slots_fail:0
cluster_known_nodes:1
cluster_size:0
cluster_current_epoch:0
cluster_my_epoch:0
cluster_stats_messages_sent:0
cluster_stats_messages_received:0
total_cluster_links_buffer_limit_exceeded:0
127.0.0.1:6379>
127.0.0.1:6379> exit
#初始化集群，ip，端口为对应pod端口
root@redis-app-0:/data# redis-cli --cluster create 10.244.1.159:6379 10.244.2.136:6379 10.244.1.158:6379 10.244.2.139:6379 10.244.1.160:6379 10.244.1.157:6379 --cluster-replicas 1
>>> Performing hash slots allocation on 6 nodes...
Master[0] -> Slots 0 - 5460
Master[1] -> Slots 5461 - 10922
Master[2] -> Slots 10923 - 16383
Adding replica 10.244.1.160:6379 to 10.244.1.159:6379
Adding replica 10.244.1.157:6379 to 10.244.2.136:6379
Adding replica 10.244.2.139:6379 to 10.244.1.158:6379
M: d97f5acc6a803cc5ae1a0fd9a405e4cbc49cb72b 10.244.1.159:6379
slots:[0-5460] (5461 slots) master
M: d52754f0c6d7774430a4bb2e3abc05111421e854 10.244.2.136:6379
slots:[5461-10922] (5462 slots) master
M: fc2e51c0afc9f8b4440e652c366033ce277f9809 10.244.1.158:6379
slots:[10923-16383] (5461 slots) master
S: e645ed14a194b8e8d7b11d6e65035f14451010b6 10.244.2.139:6379
replicates fc2e51c0afc9f8b4440e652c366033ce277f9809
S: 8d0bdcdf5af3d8b1ce751b7a68e5261ac514e0bc 10.244.1.160:6379
replicates d97f5acc6a803cc5ae1a0fd9a405e4cbc49cb72b
S: de6607e6972983f38a9b66f7bfbac1e9eb112c63 10.244.1.157:6379
replicates d52754f0c6d7774430a4bb2e3abc05111421e854
Can I set the above configuration? (type 'yes' to accept): yes
>>> Nodes configuration updated
>>> Assign a different config epoch to each node
>>> Sending CLUSTER MEET messages to join the cluster
Waiting for the cluster to join
....
>>> Performing Cluster Check (using node 10.244.1.159:6379)
M: d97f5acc6a803cc5ae1a0fd9a405e4cbc49cb72b 10.244.1.159:6379
slots:[0-5460] (5461 slots) master
1 additional replica(s)
S: e645ed14a194b8e8d7b11d6e65035f14451010b6 10.244.2.139:6379
slots: (0 slots) slave
replicates fc2e51c0afc9f8b4440e652c366033ce277f9809
S: 8d0bdcdf5af3d8b1ce751b7a68e5261ac514e0bc 10.244.1.160:6379
slots: (0 slots) slave
replicates d97f5acc6a803cc5ae1a0fd9a405e4cbc49cb72b
M: d52754f0c6d7774430a4bb2e3abc05111421e854 10.244.2.136:6379
slots:[5461-10922] (5462 slots) master
1 additional replica(s)
S: de6607e6972983f38a9b66f7bfbac1e9eb112c63 10.244.1.157:6379
slots: (0 slots) slave
replicates d52754f0c6d7774430a4bb2e3abc05111421e854
M: fc2e51c0afc9f8b4440e652c366033ce277f9809 10.244.1.158:6379
slots:[10923-16383] (5461 slots) master
1 additional replica(s)
[OK] All nodes agree about slots configuration.
>>> Check for open slots...
>>> Check slots coverage...
[OK] All 16384 slots covered.
#至此初始化集群成功
#重新进入redis集群
root@redis-app-0:/data# redis-cli -c
#查询集群信息，集群状态ok：cluster_state:ok；集群节点数6：cluster_known_nodes:6
127.0.0.1:6379> CLUSTER INFO
cluster_state:ok
cluster_slots_assigned:16384
cluster_slots_ok:16384
cluster_slots_pfail:0
cluster_slots_fail:0
cluster_known_nodes:6
cluster_size:3
cluster_current_epoch:6
cluster_my_epoch:1
cluster_stats_messages_ping_sent:94
cluster_stats_messages_pong_sent:94
cluster_stats_messages_sent:188
cluster_stats_messages_ping_received:89
cluster_stats_messages_pong_received:94
cluster_stats_messages_meet_received:5
cluster_stats_messages_received:188
total_cluster_links_buffer_limit_exceeded:0
#目前使用的主节点在10.244.1.158
127.0.0.1:6379> get a
-> Redirected to slot [15495] located at 10.244.1.158:6379
(nil)
#至此redis集群部署完成
8、主从测试
删除一个pod：redis-app-0，k8s会自动重建一个名称为：redis-app-0 的pod，名字始终保持不变，检查集群信息集群状态ok：cluster_state:ok；集群节点数6：cluster_known_nodes:6
