在Kubernetes上部署Elasticsearch集群
2018-12-13更新：
鉴于最近很多网友询问关于Elasticsearch部署的问题，主要问题在于容器操作系统的内核参数限制，在此将最新的部署文件贴出来，仅供参考：--- apiVersion: v1 kind: ServiceAccount metadata: labels: app: elasticsearch name: elasticsearch-admin namespace: ns-elastic --- apiVersion: rbac.authorization.k8s.io/v1 kind: ClusterRoleBinding metadata: name: elasticsearch-admin labels: app: elasticsearch roleRef: apiGroup: rbac.authorization.k8s.io kind: ClusterRole name: cluster-admin subjects: - kind: ServiceAccount name: elasticsearch-admin namespace: ns-elastic --- kind: Deployment apiVersion: apps/v1 metadata: labels: app: elasticsearch role: master name: elasticsearch-master namespace: ns-elastic spec: replicas: 3 revisionHistoryLimit: 10 selector: matchLabels: app: elasticsearch role: master template: metadata: labels: app: elasticsearch role: master spec: serviceAccountName: elasticsearch-admin containers: - name: elasticsearch-master image: 192.168.101.88:5000/elastic/elasticsearch:6.2.3 command: ["bash", "-c", "ulimit -l unlimited && sysctl -w vm.max_map_count=262144 && exec su elasticsearch docker-entrypoint.sh"] ports: - containerPort: 9200 protocol: TCP - containerPort: 9300 protocol: TCP env: - name: "cluster.name" value: "elasticsearch-cluster" - name: "bootstrap.memory_lock" value: "true" - name: "discovery.zen.ping.unicast.hosts" value: "elasticsearch-discovery" - name: "discovery.zen.minimum_master_nodes" value: "2" - name: "discovery.zen.ping_timeout" value: "5s" - name: "node.master" value: "true" - name: "node.data" value: "false" - name: "node.ingest" value: "false" - name: "ES_JAVA_OPTS" value: "-Xms512m -Xmx512m" securityContext: privileged: true --- kind: Service apiVersion: v1 metadata: labels: app: elasticsearch name: elasticsearch-discovery namespace: ns-elastic spec: ports: - port: 9300 targetPort: 9300 selector: app: elasticsearch role: master --- apiVersion: v1 kind: Service metadata: name: elasticsearch-data-service namespace: ns-elastic labels: app: elasticsearch role: data spec: ports: - port: 9200 name: outer - port: 9300 name: inner clusterIP: None selector: app: elasticsearch role: data --- kind: StatefulSet apiVersion: apps/v1 metadata: labels: app: elasticsearch role: data name: elasticsearch-data namespace: ns-elastic spec: replicas: 2 revisionHistoryLimit: 10 selector: matchLabels: app: elasticsearch serviceName: elasticsearch-data-service template: metadata: labels: app: elasticsearch role: data spec: serviceAccountName: elasticsearch-admin containers: - name: elasticsearch-data image: 192.168.101.88:5000/elastic/elasticsearch:6.2.3 command: ["bash", "-c", "ulimit -l unlimited && sysctl -w vm.max_map_count=262144 && chown -R elasticsearch:elasticsearch /usr/share/elasticsearch/data && exec su elasticsearch docker-entrypoint.sh"] ports: - containerPort: 9200 protocol: TCP - containerPort: 9300 protocol: TCP env: - name: "cluster.name" value: "elasticsearch-cluster" - name: "bootstrap.memory_lock" value: "true" - name: "discovery.zen.ping.unicast.hosts" value: "elasticsearch-discovery" - name: "node.master" value: "false" - name: "node.data" value: "true" - name: "ES_JAVA_OPTS" value: "-Xms1024m -Xmx1024m" volumeMounts: - name: elasticsearch-data-volume mountPath: /usr/share/elasticsearch/data securityContext: privileged: true securityContext: fsGroup: 1000 # volumes: # - name: elasticsearch-data-volume # emptyDir: {} volumeClaimTemplates: - metadata: name: elasticsearch-data-volume spec: accessModes: ["ReadWriteOnce"] storageClassName: "vsphere-volume-sc" resources: requests: storage: 15Gi --- kind: Service apiVersion: v1 metadata: labels: app: elasticsearch name: elasticsearch-service namespace: ns-elastic spec: ports: - port: 9200 targetPort: 9200 selector: app: elasticsearch --- apiVersion: extensions/v1beta1 kind: Ingress metadata: labels: app: elasticsearch name: elasticsearch-ingress namespace: ns-elastic spec: rules: - host: elasticsearch.kube.com http: paths: - backend: serviceName: elasticsearch-service servicePort: 9200如果需要定时清理历史数据，可以参考：
apiVersion: batch/v1beta1 kind: CronJob metadata: name: elasticsearch labels: app.kubernetes.io/name: elasticsearch helm.sh/chart: elasticsearch-0.1.0 app.kubernetes.io/instance: elasticsearch app.kubernetes.io/managed-by: Tiller spec: schedule: "0 1 * * *" concurrencyPolicy: Forbid jobTemplate: spec: template: spec: containers: - name: hello image: "192.168.101.88:5000/busybox:1.29.3" imagePullPolicy: IfNotPresent command: - "sh" - "-c" - > history=$(date -D '%s' +"%Y.%m.%d" -d "$(( `date +%s`-60*60*24*6 ))"); echo ${history}; hostname=elasticsearch.ns-monitor; echo ${hostname}; echo -ne "DELETE /*${history}* HTTP/1.1rnHost: ${hostname}rnrn" | nc -v -i 1 ${hostname} 9200 restartPolicy: OnFailure
------------------------------------------------原文如下------------------------------------------------
在Kubernetes上部署Elasticsearch集群
尝试在上一篇文章中搭建的K8S集群上部署ES集群，去年年中的时候，未来搭建ELK，学习过一段时间的ES，在虚拟机里搭建过简单的集群环境。现在K8S里再次搭建的时候，发现当时学过的很多概念都生疏了，又找到之前的学习记录复习了一遍——好记忆不如烂笔头。言归正传
1、环境清单
1.1、系统清单
| IP | Hostname | Role | OS |
|---|---|---|---|
| 192.168.119.160 | k8s-master | Master | CentOS 7 |
| 192.168.119.161 | k8s-node-1 | Node | CentOS 7 |
| 192.168.119.162 | k8s-node-2 | Node | CentOS 7 |
| 192.168.119.163 | k8s-node-3 | Node | CentOS 7 |
在之前的基础上多加了一个node节点，因为在两个node的时候部署ES集群，内存不够，然后一直提示提示OPENJDK GC Kill之类的信息。
1.2、镜像清单
下载地址参考：https://www.docker.elastic.co，下文附网盘下载链接。
2、部署说明
2.1、导入镜像
将镜像导入私库或者你的所有k8s节点上的docker内。
2.2、编写Dockerfile，修改镜像
[root@k8s-master dockerfile]# pwd
/root/dockerfile
[root@k8s-master dockerfile]# ll
-rw-r--r--. 1 root root 156 3月 5 16:28 Dockerfile
-rw-r--r--. 1 root root 98 3月 2 15:26 run.sh
### Dockerfile文件内容 ###
[root@k8s-master dockerfile]# vi Dockerfile
FROM docker.elastic.co/elasticsearch/elasticsearch:6.2.2
MAINTAINER chenlei leichen.china@gmail.com
COPY run.sh /
RUN chmod 775 /run.sh
CMD ["/run.sh"]
### 启动脚本内容 ###
[root@k8s-master dockerfile]# vi run.sh
#!/bin/bash
# 设置memlock无限制
ulimit -l unlimited
exec su elasticsearch /usr/local/bin/docker-entrypoint.sh
### 构建镜像 ###
[root@k8s-master dockerfile]# docker build --tag docker.elastic.co/elasticsearch/elasticsearch:6.2.2-1 .
之所以要修改镜像，是因为在k8s中不能直接修改系统参数（ulimit）。官网上的事例是在docker上部署的，docker可以通过ulimits来修改用户资源限制。但是k8s上各种尝试各种碰壁，老外也有不少争论。
通过上述方式，将镜像的入口命令修改为我们自己的run.sh，然后在脚本内设置memlock，最后调研原本的启动脚本来达到目的。
2.3、ES集群规划
Elasticsearch我选用的6.2.2的最新版本，集群节点分饰三种角色：master、data、ingest，每个节点担任至少一种角色。每个觉得均有对应的参数指定，下文将描述。
标注为master的节点表示master候选节点，具备成为master的资格，实际的master节点在运行时由其他节点投票产生，集群健康的情况下，同一时刻只有一个master节点，否则称之为脑裂，会导致数据不一致。
| ES节点（POD） | 是否Master | 是否Data | 是否Ingest |
|---|---|---|---|
| 节点1 | Y | N | N |
| 节点2 | Y | N | N |
| 节点3 | Y | N | N |
| 节点4 | N | Y | Y |
| 节点5 | N | Y | Y |
2.4、编写YML文件并部署集群
仅此一个文件：elasticsearch-cluster.yml，内容如下：
---
apiVersion: v1
kind: Namespace
metadata:
name: ns-elasticsearch
labels:
name: ns-elasticsearch
---
apiVersion: v1
kind: ServiceAccount
metadata:
labels:
elastic-app: elasticsearch
name: elasticsearch-admin
namespace: ns-elasticsearch
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
name: elasticsearch-admin
labels:
elastic-app: elasticsearch
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: cluster-admin
subjects:
- kind: ServiceAccount
name: elasticsearch-admin
namespace: ns-elasticsearch
---
kind: Deployment
apiVersion: apps/v1beta2
metadata:
labels:
elastic-app: elasticsearch
role: master
name: elasticsearch-master
namespace: ns-elasticsearch
spec:
replicas: 3
revisionHistoryLimit: 10
selector:
matchLabels:
elastic-app: elasticsearch
role: master
template:
metadata:
labels:
elastic-app: elasticsearch
role: master
spec:
containers:
- name: elasticsearch-master
image: docker.elastic.co/elasticsearch/elasticsearch:6.2.2-1
lifecycle:
postStart:
exec:
command: ["/bin/bash", "-c", "sysctl -w vm.max_map_count=262144; ulimit -l unlimited;"]
ports:
- containerPort: 9200
protocol: TCP
- containerPort: 9300
protocol: TCP
env:
- name: "cluster.name"
value: "elasticsearch-cluster"
- name: "bootstrap.memory_lock"
value: "true"
- name: "discovery.zen.ping.unicast.hosts"
value: "elasticsearch-discovery"
- name: "discovery.zen.minimum_master_nodes"
value: "2"
- name: "discovery.zen.ping_timeout"
value: "5s"
- name: "node.master"
value: "true"
- name: "node.data"
value: "false"
- name: "node.ingest"
value: "false"
- name: "ES_JAVA_OPTS"
value: "-Xms256m -Xmx256m"
securityContext:
privileged: true
serviceAccountName: elasticsearch-admin
tolerations:
- key: node-role.kubernetes.io/master
effect: NoSchedule
---
kind: Service
apiVersion: v1
metadata:
labels:
elastic-app: elasticsearch
name: elasticsearch-discovery
namespace: ns-elasticsearch
spec:
ports:
- port: 9300
targetPort: 9300
selector:
elastic-app: elasticsearch
role: master
---
kind: Deployment
apiVersion: apps/v1beta2
metadata:
labels:
elastic-app: elasticsearch
role: data
name: elasticsearch-data
namespace: ns-elasticsearch
spec:
replicas: 2
revisionHistoryLimit: 10
selector:
matchLabels:
elastic-app: elasticsearch
template:
metadata:
labels:
elastic-app: elasticsearch
role: data
spec:
containers:
- name: elasticsearch-data
image: docker.elastic.co/elasticsearch/elasticsearch:6.2.2-1
lifecycle:
postStart:
exec:
command: ["/bin/bash", "-c", "sysctl -w vm.max_map_count=262144; ulimit -l unlimited;"]
ports:
- containerPort: 9200
protocol: TCP
- containerPort: 9300
protocol: TCP
volumeMounts:
- name: esdata
mountPath: /usr/share/elasticsearch/data
env:
- name: "cluster.name"
value: "elasticsearch-cluster"
- name: "bootstrap.memory_lock"
value: "true"
- name: "discovery.zen.ping.unicast.hosts"
value: "elasticsearch-discovery"
- name: "node.master"
value: "false"
- name: "node.data"
value: "true"
- name: "ES_JAVA_OPTS"
value: "-Xms256m -Xmx256m"
securityContext:
privileged: true
volumes:
- name: esdata
emptyDir: {}
serviceAccountName: elasticsearch-admin
tolerations:
- key: node-role.kubernetes.io/master
effect: NoSchedule
---
kind: Service
apiVersion: v1
metadata:
labels:
elastic-app: elasticsearch-service
name: elasticsearch-service
namespace: ns-elasticsearch
spec:
ports:
- port: 9200
targetPort: 9200
selector:
elastic-app: elasticsearch
type: NodePort
通过环境变量设置：node.master、node.data和node.ingest来控制对应的角色，三个选项的默认值均是true；
通过postStart来设置系统内核参数，但是对memlock无效；网上也有通过initPod进行修改的，暂时没有尝试过。
通过设置discovery.zen.minimum_master_nodes来防止脑裂，表示多少个master候选节点在线时集群可用；
通过设置discovery.zen.ping_timeout来降低网络延时带来的脑裂现象；
节点通过单播来发现和加入进群，设置elasticsearch-discovery服务作为进群发现入口；
serviceAccount是否有必要带验证！
### 在K8S上发布ES集群 ###
[root@k8s-master elasticsearch-cluster]# kubectl apply -f elasticsearch-cluster.yml
2.5、检查并测试集群
[root@k8s-master elasticsearch-cluster]# kubectl get pods --all-namespaces
NAMESPACE NAME READY STATUS RESTARTS AGE
kube-system etcd-k8s-master 1/1 Running 7 5d
kube-system kube-apiserver-k8s-master 1/1 Running 7 5d
kube-system kube-controller-manager-k8s-master 1/1 Running 4 5d
kube-system kube-dns-6f4fd4bdf-mwddx 3/3 Running 10 5d
kube-system kube-flannel-ds-nwxcl 1/1 Running 5 5d
kube-system kube-flannel-ds-pdxhs 1/1 Running 5 5d
kube-system kube-flannel-ds-qgbmf 1/1 Running 3 5h
kube-system kube-flannel-ds-qrkwd 1/1 Running 3 5d
kube-system kube-proxy-7lsqw 1/1 Running 5 5d
kube-system kube-proxy-bq6kg 1/1 Running 0 5h
kube-system kube-proxy-f9kps 1/1 Running 5 5d
kube-system kube-proxy-g47nx 1/1 Running 3 5d
kube-system kube-scheduler-k8s-master 1/1 Running 4 5d
kube-system kubernetes-dashboard-845747bdd4-gcj47 1/1 Running 3 5d
ns-elasticsearch elasticsearch-master-65c8cc584c-jcsq4 1/1 Running 0 4h
ns-elasticsearch elasticsearch-master-65c8cc584c-kwg69 1/1 Running 0 4h
ns-elasticsearch elasticsearch-master-65c8cc584c-rdcbz 1/1 Running 0 4h
ns-elasticsearch elasticsearch-node-6f9d5fbd6c-6jktr 1/1 Running 0 4h
ns-elasticsearch elasticsearch-node-6f9d5fbd6c-x7qk8 1/1 Running 0 4h
[root@k8s-master elasticsearch-cluster]# kubectl get svc --all-namespaces
NAMESPACE NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
default kubernetes ClusterIP 10.96.0.1 443/TCP 5d
kube-system kube-dns ClusterIP 10.96.0.10 53/UDP,53/TCP 5d
kube-system kubernetes-dashboard NodePort 10.111.158.221 443:32286/TCP 5d
ns-elasticsearch elasticsearch-discovery ClusterIP 10.97.150.85 9300/TCP 1m
ns-elasticsearch elasticsearch-service NodePort 10.101.40.47 9200:31112/TCP 1m
上图中的node.role包含mdi，分别对呀master、data和ingest。
3、注意事项
- 如果k8s节点内存不够，可能导致部分ES节点报错
- 集群发现通过k8s service来实现，ES本身“discovery.zen.ping.unicast.hosts”也不需要配置所有节点列表，新节点只需要连上集群中任意一个有效节点即可找到全部
- ulimit -l unlimited无法在postStart中生效
- 在dashboard中可以比较方便的查看日志，当然也可以使用kubectl log命令，查看日志可以快速定位问题
- 尝试增加数据节点
[root@k8s-master ~]# kubectl scale deployment elasticsearch-data --replicas 3 -n ns-elasticsearch
[root@k8s-master ~]# kubectl get pods --all-namespaces
NAMESPACE NAME READY STATUS RESTARTS AGE
kube-system etcd-k8s-master 1/1 Running 8 5d
kube-system kube-apiserver-k8s-master 1/1 Running 8 5d
kube-system kube-controller-manager-k8s-master 1/1 Running 5 5d
kube-system kube-dns-6f4fd4bdf-mwddx 3/3 Running 13 5d
kube-system kube-flannel-ds-nwxcl 1/1 Running 6 5d
kube-system kube-flannel-ds-pdxhs 1/1 Running 6 5d
kube-system kube-flannel-ds-qgbmf 1/1 Running 4 21h
kube-system kube-flannel-ds-qrkwd 1/1 Running 4 5d
kube-system kube-proxy-7lsqw 1/1 Running 6 5d
kube-system kube-proxy-bq6kg 1/1 Running 1 21h
kube-system kube-proxy-f9kps 1/1 Running 6 5d
kube-system kube-proxy-g47nx 1/1 Running 4 5d
kube-system kube-scheduler-k8s-master 1/1 Running 5 5d
kube-system kubernetes-dashboard-845747bdd4-gcj47 1/1 Running 4 5d
ns-elasticsearch elasticsearch-data-657bb6c8f9-gpv89 1/1 Running 0 9s
ns-elasticsearch elasticsearch-data-657bb6c8f9-jbrkc 1/1 Running 1 15h
ns-elasticsearch elasticsearch-data-657bb6c8f9-pzmj5 1/1 Running 1 15h
ns-elasticsearch elasticsearch-master-976859f58-qltf5 1/1 Running 1 15h
ns-elasticsearch elasticsearch-master-976859f58-ts65d 1/1 Running 1 15h
ns-elasticsearch elasticsearch-master-976859f58-zwqgv 1/1 Running 1 15h
上图出现新节点可能需要等待一分钟左右
4、附件下载
网盘地址：https://pan.baidu.com/s/1PN0ku0BNYWZUI_5moXS9cA
解压：
[root@k8s-master elasticsearch-cluster]# tar -zxvf elasticsearch-6.2.2.tar.gz elasticsearch-6.2.2.tar导入：
[root@k8s-master elasticsearch-cluster]# docker load -i elasticsearch-6.2.2.tar
5、参考资料
- http://blog.csdn.net/zwgdft/article/details/54585644
- http://blog.csdn.net/zwgdft/article/details/54585644
- http://blog.csdn.net/a19860903/article/details/72467996
- https://www.elastic.co/guide/en/elasticsearch/reference/6.2/docker.html
- https://github.com/cesargomezvela/elasticsearch
- https://github.com/kubernetes/kubernetes/issues/3595
文章来源于互联网:在Kubernetes上部署Elasticsearch集群
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