前面介绍并初试了es6.5系列的单节点的操作,现在搭建es6.5系列的集群:
环境:三节点:master-172.16.23.128.node1-172.16.23.129.node2-172.16.23.130,首先查看es的服务状态:
[root@master ~]# ansible all_nodes -m shell -a "systemctl status elasticsearch"|grep -i running Active: active (running) since 六 2018-12-29 12:06:55 CST; 3h 33min ago Active: active (running) since 六 2018-12-29 12:07:43 CST; 3h 32min ago Active: active (running) since 六 2018-12-29 15:38:47 CST; 1min 42s ago
查看各节点上面的es的配置文件:
[root@master ~]# ansible all_nodes -m shell -a 'cat /etc/elasticsearch/elasticsearch.yml|egrep -v "^$|^#"' 172.16.23.128 | CHANGED | rc=0 >> cluster.name: estest node.name: esnode2 path.data: /var/lib/elasticsearch path.logs: /var/log/elasticsearch network.host: 0.0.0.0 http.port: 9200 discovery.zen.ping.unicast.hosts: ["172.16.23.128", "172.16.23.131"] 172.16.23.130 | CHANGED | rc=0 >> path.data: /var/lib/elasticsearch path.logs: /var/log/elasticsearch 172.16.23.129 | CHANGED | rc=0 >> cluster.name: es node.name: node1 path.data: /var/lib/elasticsearch path.logs: /var/log/elasticsearch network.host: 0.0.0.0 http.port: 9200
现在基于discovery.zen做集群配置参考:https://www.elastic.co/guide/en/elasticsearch/reference/6.5/modules-discovery-zen.html,具体配置如下:
[root@master ~]# ansible all_nodes -m shell -a 'cat /etc/elasticsearch/elasticsearch.yml|egrep -v "^$|^#"' 172.16.23.128 | CHANGED | rc=0 >> cluster.name: estest node.name: master path.data: /var/lib/elasticsearch path.logs: /var/log/elasticsearch network.host: 0.0.0.0 http.port: 9200 discovery.zen.ping.unicast.hosts: ["172.16.23.128", "172.16.23.129", "172.16.23.130"] 172.16.23.130 | CHANGED | rc=0 >> cluster.name: estest node.name: node2 path.data: /var/lib/elasticsearch path.logs: /var/log/elasticsearch network.host: 0.0.0.0 http.port: 9200 discovery.zen.ping.unicast.hosts: ["172.16.23.128", "172.16.23.129", "172.16.23.130"] 172.16.23.129 | CHANGED | rc=0 >> cluster.name: estest node.name: node1 path.data: /var/lib/elasticsearch path.logs: /var/log/elasticsearch network.host: 0.0.0.0 http.port: 9200 discovery.zen.ping.unicast.hosts: ["172.16.23.128", "172.16.23.129", "172.16.23.130"]
重启elasticsearch服务:
[root@master ~]# ansible all_nodes -m shell -a "systemctl restart elasticsearch" 172.16.23.130 | CHANGED | rc=0 >> 172.16.23.128 | CHANGED | rc=0 >> 172.16.23.129 | CHANGED | rc=0 >>
然后查看集群状态:
[root@master ~]# curl -X GET "localhost:9200/_cluster/health" -s|python -m json.tool
{
"active_primary_shards": 0,
"active_shards": 0,
"active_shards_percent_as_number": 100.0,
"cluster_name": "estest",
"delayed_unassigned_shards": 0,
"initializing_shards": 0,
"number_of_data_nodes": 3,
"number_of_in_flight_fetch": 0,
"number_of_nodes": 3,
"number_of_pending_tasks": 0,
"relocating_shards": 0,
"status": "green",
"task_max_waiting_in_queue_millis": 0,
"timed_out": false,
"unassigned_shards": 0
}
查看节点个数:
[root@master ~]# curl -X GET "localhost:9200/_cat/nodes?v" ip heap.percent ram.percent cpu load_1m load_5m load_15m node.role master name 172.16.23.128 28 71 3 0.04 0.11 0.08 mdi * master 172.16.23.130 29 67 4 0.04 0.11 0.10 mdi - node2 172.16.23.129 28 58 4 0.12 0.20 0.13 mdi - node1
单单只看master节点:
[root@master ~]# curl -X GET "localhost:9200/_cat/master?v" id host ip node hVY-U_ocQueMtcryoGGbTg 172.16.23.128 172.16.23.128 master
查看集群health:
[root@master ~]# curl -X GET "localhost:9200/_cat/health?v" epoch timestamp cluster status node.total node.data shards pri relo init unassign pending_tasks max_task_wait_time active_shards_percent 1546070536 08:02:16 estest green 3 3 0 0 0 0 0 0 - 100.0%
查看nodeattrs属性:
[root@master ~]# curl -X GET "localhost:9200/_cat/nodeattrs?v" node host ip attr value master 172.16.23.128 172.16.23.128 ml.machine_memory 3956293632 master 172.16.23.128 172.16.23.128 xpack.installed true master 172.16.23.128 172.16.23.128 ml.max_open_jobs 20 master 172.16.23.128 172.16.23.128 ml.enabled true node2 172.16.23.130 172.16.23.130 ml.machine_memory 3956293632 node2 172.16.23.130 172.16.23.130 ml.max_open_jobs 20 node2 172.16.23.130 172.16.23.130 xpack.installed true node2 172.16.23.130 172.16.23.130 ml.enabled true node1 172.16.23.129 172.16.23.129 ml.machine_memory 3956293632 node1 172.16.23.129 172.16.23.129 ml.max_open_jobs 20 node1 172.16.23.129 172.16.23.129 xpack.installed true node1 172.16.23.129 172.16.23.129 ml.enabled true
现在手动创建一个index为test:
# curl -X PUT "localhost:9200/test"
然后查看各节点index情况:
[root@master ~]# ansible all_nodes -m shell -a 'curl -X GET "localhost:9200/_cat/indices?v" -s' [WARNING]: Consider using the get_url or uri module rather than running curl. If you need to use command because get_url or uri is insufficient you can add warn=False to this command task or set command_warnings=False in ansible.cfg to get rid of this message. 172.16.23.128 | CHANGED | rc=0 >> health status index uuid pri rep docs.count docs.deleted store.size pri.store.size yellow open test l0Js1PJLTPSFEdXhanVSHA 5 1 0 0 1.7kb 1.1kb 172.16.23.130 | CHANGED | rc=0 >> health status index uuid pri rep docs.count docs.deleted store.size pri.store.size yellow open test l0Js1PJLTPSFEdXhanVSHA 5 1 0 0 1.7kb 1.1kb 172.16.23.129 | CHANGED | rc=0 >> health status index uuid pri rep docs.count docs.deleted store.size pri.store.size yellow open test l0Js1PJLTPSFEdXhanVSHA 5 1 0 0 1.7kb 1.1kb
查看index的分片情况:
[root@master ~]# curl -X GET "localhost:9200/_cat/shards?v" index shard prirep state docs store ip node test 3 p STARTED 0 230b 172.16.23.128 master test 3 r STARTED 0 230b 172.16.23.130 node2 test 2 r STARTED 0 230b 172.16.23.129 node1 test 2 p STARTED 0 230b 172.16.23.130 node2 test 1 p STARTED 0 230b 172.16.23.129 node1 test 1 r UNASSIGNED test 4 p STARTED 0 230b 172.16.23.129 node1 test 4 r UNASSIGNED test 0 p STARTED 0 230b 172.16.23.128 master test 0 r STARTED 0 230b 172.16.23.130 node2
由上面可以看出有两个分片是UNASSIGNED状态,查看集群health:
[root@master ~]# curl -X GET "localhost:9200/_cat/health?v" epoch timestamp cluster status node.total node.data shards pri relo init unassign pending_tasks max_task_wait_time active_shards_percent 1546071645 08:20:45 estest yellow 3 3 8 5 0 0 2 0 - 80.0%
使用下面的命令定位有问题的分片以及原因:
[root@master ~]# curl -XGET localhost:9200/_cat/shards?h=index,shard,prirep,state,unassigned.reason -s| grep UNASSIGNED test 1 r UNASSIGNED INDEX_CREATED test 4 r UNASSIGNED INDEX_CREATED
获取分片更多信息:
[root@master ~]# curl -XGET localhost:9200/_cluster/allocation/explain?pretty
{
"index" : "test",
"shard" : 1,
"primary" : false,
"current_state" : "unassigned",
"unassigned_info" : {
"reason" : "INDEX_CREATED",
"at" : "2018-12-29T08:14:47.378Z",
"last_allocation_status" : "no_attempt"
},
"can_allocate" : "no",
"allocate_explanation" : "cannot allocate because allocation is not permitted to any of the nodes",
"node_allocation_decisions" : [
{
"node_id" : "hVY-U_ocQueMtcryoGGbTg",
"node_name" : "master",
"transport_address" : "172.16.23.128:9300",
"node_attributes" : {
"ml.machine_memory" : "3956293632",
"xpack.installed" : "true",
"ml.max_open_jobs" : "20",
"ml.enabled" : "true"
},
"node_decision" : "no",
"weight_ranking" : 1,
"deciders" : [
{
"decider" : "node_version",
"decision" : "NO",
"explanation" : "cannot allocate replica shard to a node with version [6.5.2] since this is older than the primary version [6.5.4]"
}
]
},
{
"node_id" : "q95yZ4W4Tj6PaXyzLZZYDQ",
"node_name" : "node1",
"transport_address" : "172.16.23.129:9300",
"node_attributes" : {
"ml.machine_memory" : "3956293632",
"ml.max_open_jobs" : "20",
"xpack.installed" : "true",
"ml.enabled" : "true"
},
"node_decision" : "no",
"weight_ranking" : 2,
"deciders" : [
{
"decider" : "same_shard",
"decision" : "NO",
"explanation" : "the shard cannot be allocated to the same node on which a copy of the shard already exists [[test][1], node[q95yZ4W4Tj6PaXyzLZZYDQ], [P], s[STARTED], a[id=j7V8PBUvQnOZzISPAxK9Uw]]"
}
]
},
{
"node_id" : "_ADSWG04TEqNfX_88ejtzQ",
"node_name" : "node2",
"transport_address" : "172.16.23.130:9300",
"node_attributes" : {
"ml.machine_memory" : "3956293632",
"ml.max_open_jobs" : "20",
"xpack.installed" : "true",
"ml.enabled" : "true"
},
"node_decision" : "no",
"weight_ranking" : 3,
"deciders" : [
{
"decider" : "node_version",
"decision" : "NO",
"explanation" : "cannot allocate replica shard to a node with version [6.5.2] since this is older than the primary version [6.5.4]"
}
]
}
]
}
由上面结果可知node1,node2的es版本不同于master的es版本:
[root@master ~]# ansible all_nodes -m shell -a 'rpm -qa|grep elasticsearch' [WARNING]: Consider using the yum, dnf or zypper module rather than running rpm. If you need to use command because yum, dnf or zypper is insufficient you can add warn=False to this command task or set command_warnings=False in ansible.cfg to get rid of this message. 172.16.23.128 | CHANGED | rc=0 >> elasticsearch-6.5.2-1.noarch 172.16.23.130 | CHANGED | rc=0 >> elasticsearch-6.5.2-1.noarch 172.16.23.129 | CHANGED | rc=0 >> elasticsearch-6.5.4-1.noarch
将其中上面版本不一致的替换掉后,开启es服务,然后观察集群以及shards情况:
[root@master ~]# curl -X GET "localhost:9200/_cat/health?v" epoch timestamp cluster status node.total node.data shards pri relo init unassign pending_tasks max_task_wait_time active_shards_percent 1546073143 08:45:43 estest red 1 1 2 2 0 0 8 0 - 20.0% [root@master ~]# curl -X GET "localhost:9200/_cat/health?v" epoch timestamp cluster status node.total node.data shards pri relo init unassign pending_tasks max_task_wait_time active_shards_percent 1546073274 08:47:54 estest green 3 3 10 5 0 0 0 0 - 100.0%
[root@master ~]# curl -X GET "localhost:9200/_cat/shards?v" index shard prirep state docs store ip node test 3 p STARTED 0 261b 172.16.23.128 master test 3 r STARTED 0 261b 172.16.23.130 node2 test 4 r STARTED 0 261b 172.16.23.128 master test 4 p STARTED 0 261b 172.16.23.129 node1 test 2 r STARTED 0 261b 172.16.23.129 node1 test 2 p STARTED 0 261b 172.16.23.130 node2 test 1 p STARTED 0 261b 172.16.23.129 node1 test 1 r STARTED 0 261b 172.16.23.130 node2 test 0 p STARTED 0 261b 172.16.23.128 master test 0 r STARTED 0 261b 172.16.23.130 node2
索引test由10个分片组成,五个主分片,5个replica shard,replica shard是primary shard的副本，负责容错，以及承担读请求负载,primary shard的数量在创建索引的时候就固定了，replica shard的数量可以随时修改,primary shard的默认数量是5，replica默认是1
[root@master ~]# curl -XGET localhost:9200/test?pretty
{
"test" : {
"aliases" : { },
"mappings" : { },
"settings" : {
"index" : {
"creation_date" : "1546071287243",
"number_of_shards" : "5",
"number_of_replicas" : "1",
"uuid" : "l0Js1PJLTPSFEdXhanVSHA",
"version" : {
"created" : "6050299"
},
"provided_name" : "test"
}
}
}
}
[root@master ~]# curl -XGET localhost:9200/_cat/indices?v health status index uuid pri rep docs.count docs.deleted store.size pri.store.size green open test l0Js1PJLTPSFEdXhanVSHA 5 1 0 0 2.5kb 1.2kb
primary shard不能和自己的replica shard放在同一个节点上（否则节点宕机，primary shard和副本都丢失，起不到容错的作用），但是可以和其他primary shard的replica shard放在 同一个节点上
节点以及shards数分配参考:https://blog.csdn.net/qq_38486203/article/details/80077844
然后这里梳理一下es中一些基础概念:
1.cluster:
集群，一个ES集群由一个或多个节点（Node）组成，每个集群都有一个cluster name作为标识
2.node:
节点，一个ES实例就是一个node，一个机器可以有多个实例，一个集群由多个节点构成,大多数情况下每个node运行在一个独立的环境或虚拟机上。
3.index:
索引，即一系列documents的集合
3.shard:
分片，ES是分布式搜索引擎，每个索引有一个或多个分片，索引的数据被分配到各个分片上，相当于一桶水用了N个杯子装
分片有助于横向扩展，N个分片会被尽可能平均地（rebalance）分配在不同的节点上（例如你有2个节点，4个主分片(不考虑备份)，那么每个节点会分到2个分片，后来你增加了2个节点，那么你这4个节点上都会有1个分片，这个过程叫relocation，ES感知后自动完成)
分片是独立的，对于一个Search Request的行为，每个分片都会执行这个Request.另外每个分片都是一个Lucene Index，所以一个分片只能存放 Integer.MAX_VALUE - 128 = 2,147,483,519 个docs
4.replica:
复制，可以理解为备份分片，相应地有primary shard（主分片）
主分片和备分片不会出现在同一个节点上（防止单点故障），默认情况下一个索引创建5个分片一个备份（即5primary+5replica=10个分片）
如果你只有一个节点，那么5个replica都无法分配（unassigned），此时cluster status会变成Yellow。
ES集群的三种状态:
Green: 所有主分片和备份分片都准备就绪,分配成功, 即使有一台机器挂了(假设一台机器实例),数据都不会丢失,但是会变成yellow状态.
Yellow: 所有主分片准备就绪,但至少一个主分片(假设是A)对应的备份分片没有就绪,此时集群处于告警状态,意味着高可用和容灾能力下降.如果刚好A所在的机器挂了,并且你只设置了一个备份(已处于未继续状态), 那么A的数据就会丢失(查询不完整),此时集群处于Red状态.
Red:至少有一个主分片没有就绪(直接原因是找不到对应的备份分片成为新的主分片),此时查询的结果会出现数据丢失(不完整).
容灾：primary分片丢失，replica分片就会被顶上去成为新的主分片，同时根据这个新的主分片创建新的replica，集群数据安然无恙
提高查询性能：replica和primary分片的数据是相同的，所以对于一个query既可以查主分片也可以查备分片，在合适的范围内多个replica性能会更优（但要考虑资源占用也会提升[cpu/disk/heap]），另外index request只能发生在主分片上，replica不能执行index request。
对于一个索引，除非重建索引否则不能调整分片的数目（主分片数, number_of_shards），但可以随时调整replica数(number_of_replicas)。