kubeasz/docs/practice/es_cluster.md

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# Elasticsearch 部署实践
`Elasticsearch`是目前全文搜索引擎的首选,它可以快速地储存、搜索和分析海量数据;也可以看成是真正分布式的高效数据库集群;`Elastic`的底层是开源库`Lucene`;封装并提供了`REST API`的操作接口。
## 单节点 docker 测试安装
``` bash
cat > es-start.sh << EOF
#!/bin/bash
sysctl -w vm.max_map_count=262144
docker run --detach \
--name es01 \
-p 9200:9200 -p 9300:9300 \
-e "discovery.type=single-node" \
-e "bootstrap.memory_lock=true" --ulimit memlock=-1:-1 \
--ulimit nofile=65536:65536 \
--volume /srv/elasticsearch/data:/usr/share/elasticsearch/data \
--volume /srv/elasticsearch/elasticsearch.yml:/usr/share/elasticsearch/config/elasticsearch.yml \
jmgao1983/elasticsearch:6.4.0
EOF
```
执行`sh es-start.sh`后,就在本地运行了。
- 验证 docker 镜像运行情况
``` bash
root@docker-ts:~# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
171f3fecb596 jmgao1983/elasticsearch:6.4.0 "/usr/local/bin/do..." 2 hours ago Up 2 hours 0.0.0.0:9200->9200/tcp, 0.0.0.0:9300->9300/tcp es01
```
- 验证 es 健康检查
``` bash
root@docker-ts:~# curl http://127.0.0.1:9200/_cat/health
epoch timestamp cluster status node.total node.data shards pri relo init unassign pending_tasks max_task_wait_time active_shards_percent
1535523956 06:25:56 docker-es green 1 1 0 0 0 0 0 0 - 100.0%
```
## 在 k8s 上部署 Elasticsearch 集群
在生产环境下Elasticsearch 集群由不同的角色节点组成:
- master 节点参与主节点选举不存储数据建议3个以上维护整个集群的稳定可靠状态
- data 节点:不参与选主,负责存储数据;主要消耗磁盘,内存
- client 节点:不参与选主,不存储数据;负责处理用户请求,实现请求转发,负载均衡等功能
这里使用`helm chart`来部署 (https://github.com/helm/charts/tree/master/incubator/elasticsearch)
- 1.安装 helm: 以本项目[安全安装helm](../guide/helm.md)为例
- 2.准备 PV: 以本项目[K8S 集群存储](../setup/08-cluster-storage.md)创建`nfs`动态 PV 为例
- 编辑配置文件roles/cluster-storage/defaults/main.yml
``` bash
storage:
nfs:
enabled: "yes"
server: "192.168.1.8"
server_path: "/share"
storage_class: "nfs-es"
provisioner_name: "nfs-provisioner-01"
```
- 创建 nfs provisioner
``` bash
$ ansible-playbook /etc/ansible/roles/cluster-storage/cluster-storage.yml
# 执行成功后验证
$ kubectl get pod --all-namespaces |grep nfs-prov
kube-system nfs-provisioner-01-6b7fbbf9d4-bh8lh 1/1 Running 0 1d
```
- 3.安装 elasticsearch chart
``` bash
$ cd /etc/ansible/manifests/es-cluster
# 如果你的helm安装没有启用tls证书请忽略以下--tls参数
$ helm install --tls --name es-cluster --namespace elastic -f es-values.yaml elasticsearch
```
- 4.验证 es 集群
``` bash
# 验证k8s上 es集群状态
$ kubectl get pod,svc -n elastic
NAME READY STATUS RESTARTS AGE
pod/es-cluster-elasticsearch-client-778df74c8f-7fj4k 1/1 Running 0 2m17s
pod/es-cluster-elasticsearch-client-778df74c8f-skh8l 1/1 Running 0 2m3s
pod/es-cluster-elasticsearch-data-0 1/1 Running 0 25m
pod/es-cluster-elasticsearch-data-1 1/1 Running 0 11m
pod/es-cluster-elasticsearch-master-0 1/1 Running 0 25m
pod/es-cluster-elasticsearch-master-1 1/1 Running 0 12m
pod/es-cluster-elasticsearch-master-2 1/1 Running 0 10m
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/es-cluster-elasticsearch-client NodePort 10.68.157.105 <none> 9200:29200/TCP,9300:29300/TCP 25m
service/es-cluster-elasticsearch-discovery ClusterIP None <none> 9300/TCP 25m
# 验证 es集群本身状态
$ curl $NODE_IP:29200/_cat/health
1539335131 09:05:31 es-on-k8s green 7 2 0 0 0 0 0 0 - 100.0%
$ curl $NODE_IP:29200/_cat/indices?v
health status index uuid pri rep docs.count docs.deleted store.size pri.store.size
root@k8s401:/etc/ansible# curl 10.100.97.41:29200/_cat/nodes?
172.31.2.4 27 80 5 0.09 0.11 0.21 mi - es-cluster-elasticsearch-master-0
172.31.1.7 30 97 3 0.39 0.29 0.27 i - es-cluster-elasticsearch-client-778df74c8f-skh8l
172.31.3.7 20 97 3 0.11 0.17 0.18 i - es-cluster-elasticsearch-client-778df74c8f-7fj4k
172.31.1.5 8 97 5 0.39 0.29 0.27 di - es-cluster-elasticsearch-data-0
172.31.2.5 8 80 3 0.09 0.11 0.21 di - es-cluster-elasticsearch-data-1
172.31.1.6 18 97 4 0.39 0.29 0.27 mi - es-cluster-elasticsearch-master-2
172.31.3.6 20 97 4 0.11 0.17 0.18 mi * es-cluster-elasticsearch-master-1
```
### es 性能压测
如上已使用 chart 在 k8s上部署了 **7** 节点的 elasticsearch 集群;各位应该十分好奇性能怎么样;官方提供了压测工具[esrally](https://github.com/elastic/rally)可以方便的进行性能压测,这里省略安装和测试过程;压测机上执行:
`esrally --track=http_logs --target-hosts="$NODE_IP:29200" --pipeline=benchmark-only --report-file=report.md`
压测过程需要1-2个小时部分压测结果如下
``` bash
------------------------------------------------------
_______ __ _____
/ ____(_)___ ____ _/ / / ___/_________ ________
/ /_ / / __ \/ __ `/ / \__ \/ ___/ __ \/ ___/ _ \
/ __/ / / / / / /_/ / / ___/ / /__/ /_/ / / / __/
/_/ /_/_/ /_/\__,_/_/ /____/\___/\____/_/ \___/
------------------------------------------------------
| Lap | Metric | Task | Value | Unit |
|------:|-------------------------------------:|-------------:|------------:|--------:|
...
| All | Min Throughput | index-append | 16903.2 | docs/s |
| All | Median Throughput | index-append | 17624.4 | docs/s |
| All | Max Throughput | index-append | 19382.8 | docs/s |
| All | 50th percentile latency | index-append | 1865.74 | ms |
| All | 90th percentile latency | index-append | 3708.04 | ms |
| All | 99th percentile latency | index-append | 6379.49 | ms |
| All | 99.9th percentile latency | index-append | 8389.74 | ms |
| All | 99.99th percentile latency | index-append | 9612.84 | ms |
| All | 100th percentile latency | index-append | 9861.02 | ms |
| All | 50th percentile service time | index-append | 1865.74 | ms |
| All | 90th percentile service time | index-append | 3708.04 | ms |
| All | 99th percentile service time | index-append | 6379.49 | ms |
| All | 99.9th percentile service time | index-append | 8389.74 | ms |
| All | 99.99th percentile service time | index-append | 9612.84 | ms |
| All | 100th percentile service time | index-append | 9861.02 | ms |
| All | error rate | index-append | 0 | % |
| All | Min Throughput | default | 0.66 | ops/s |
| All | Median Throughput | default | 0.66 | ops/s |
| All | Max Throughput | default | 0.66 | ops/s |
| All | 50th percentile latency | default | 770131 | ms |
| All | 90th percentile latency | default | 825511 | ms |
| All | 99th percentile latency | default | 838030 | ms |
| All | 100th percentile latency | default | 839382 | ms |
| All | 50th percentile service time | default | 1539.4 | ms |
| All | 90th percentile service time | default | 1635.39 | ms |
| All | 99th percentile service time | default | 1728.02 | ms |
| All | 100th percentile service time | default | 1736.2 | ms |
| All | error rate | default | 0 | % |
...
```
从测试结果看集群的吞吐可以k8s es-client pod还可以扩展延迟略高一些因为使用了nfs共享存储整体效果不错。
### 中文分词安装
安装 ik 插件即可可以自定义已安装ik插件的es docker镜像创建如下 Dockerfile
``` bash
FROM jmgao1983/elasticsearch:6.4.0
RUN /usr/share/elasticsearch/bin/elasticsearch-plugin install \
--batch https://github.com/medcl/elasticsearch-analysis-ik/releases/download/v6.4.0/elasticsearch-analysis-ik-6.4.0.zip \
&& cp /usr/share/zoneinfo/Asia/Shanghai /etc/localtime
```
### 参考阅读
1. [Elasticsearch 入门教程](http://www.ruanyifeng.com/blog/2017/08/elasticsearch.html)
2. [Elasticsearch 压测方案之 esrally 简介](https://segmentfault.com/a/1190000011174694)