MongoDB主备仲裁节点关闭顺序
MongoDB分为三个角色节点:Primary(P)、Secondary(S)、Arbiter(A),但是关闭顺序不正确,关闭时就会有问题,有些时候,关闭后启动也会有问题。
因此需要有一个正确的顺序来关闭MongoDB集群。下方为实验顺序:
1:关闭顺序PSA :会报错
2:关闭顺序PAS :可以
3:关闭顺序SAP :主节点会变为从节点
4:关闭顺序SPA :会报错
5:关闭顺序APS
6:关闭顺序ASP :主节点会变为从节点
服务查看:
gechongrepl:PRIMARY> rs.isMaster()
{
"setName" : "gechongrepl",
"setVersion" : 13,
"ismaster" : true,
"secondary" : false,
"hosts" : [
"192.168.91.133:27017",
"192.168.91.132:27017",
"192.168.91.132:27018"
],
"arbiters" : [
"192.168.91.135:27017"
],
"primary" : "192.168.91.133:27017",
"me" : "192.168.91.133:27017",
"electionId" : ObjectId("5568098a6de3d53a2ea91c64"),
"maxBsonObjectSize" : 16777216,
"maxMessageSizeBytes" : 48000000,
"maxWriteBatchSize" : 1000,
"localTime" : ISODate("2015-05-29T06:39:36.548Z"),
"maxWireVersion" : 3,
"minWireVersion" : 0,
"ok" : 1
}
1:关闭顺序PSA
P:
gechongrepl:PRIMARY> use admin
switched to db admin
gechongrepl:PRIMARY> db.shutdownServer()
S:
从变为了:gechongrepl:PRIMARY>
<br><br>gechongrepl:PRIMARY> use admin
switched to db admin
gechongrepl:PRIMARY> db.shutdownServer()
assert failed : unexpected error: Error: shutdownServer failed: No electable secondaries caught up as of 2015-05-28T23:48:06.022-0700
Error: assert failed : unexpected error: Error: shutdownServer failed: No electable secondaries caught up as of 2015-05-28T23:48:06.022-0700
at Error (<anonymous>)
at doassert (src/mongo/shell/assert.js:11:14)
at assert (src/mongo/shell/assert.js:20:5)
at DB.shutdownServer (src/mongo/shell/db.js:212:9)
at (shell):1:4
2015-05-28T23:48:06.023-0700 E QUERY Error: assert failed : unexpected error: Error: shutdownServer failed: No electable secondaries caught up as of 2015-05-28T23:48:06.022-0700
at Error (<anonymous>)
at doassert (src/mongo/shell/assert.js:11:14)
at assert (src/mongo/shell/assert.js:20:5)
at DB.shutdownServer (src/mongo/shell/db.js:212:9)
at (shell):1:4 at src/mongo/shell/assert.js:13
A:
gechongrepl:ARBITER> use admin
switched to db admin
gechongrepl:ARBITER> db.shutdownServer()
再关闭S:
S变为了:ggechongrepl:SECONDARY>
gechongrepl:SECONDARY> use admin
switched to db admin
gechongrepl:SECONDARY> db.shutdownServer()
2:关闭顺序PAS : 已经验证,不报错。
3:关闭顺序SAP
S:
gechongrepl:SECONDARY> use admin
switched to db admin
gechongrepl:SECONDARY> db.shutdownServer()
A:
gechongrepl:ARBITER> use admin
switched to db admin
gechongrepl:ARBITER> db.shutdownServer()
P:
主变为了:gechongrepl:SECONDARY>
gechongrepl:SECONDARY> use admin
switched to db admin
gechongrepl:SECONDARY> db.shutdownServer()
4:关闭顺序SPA
S:
gechongrepl:SECONDARY> use admin
switched to db admin
gechongrepl:SECONDARY> db.shutdownServer()
P:
gechongrepl:PRIMARY> use admin
switched to db admin
gechongrepl:PRIMARY> db.shutdownServer()
assert failed : unexpected error: Error: shutdownServer failed: No electable secondaries caught up as of 2015-05-28T23:59:19.685-0700
Error: assert failed : unexpected error: Error: shutdownServer failed: No electable secondaries caught up as of 2015-05-28T23:59:19.685-0700
at Error (<anonymous>)
at doassert (src/mongo/shell/assert.js:11:14)
at assert (src/mongo/shell/assert.js:20:5)
at DB.shutdownServer (src/mongo/shell/db.js:212:9)
at (shell):1:4
2015-05-28T23:59:19.702-0700 E QUERY Error: assert failed : unexpected error: Error: shutdownServer failed: No electable secondaries caught up as of 2015-05-28T23:59:19.685-0700
at Error (<anonymous>)
at doassert (src/mongo/shell/assert.js:11:14)
at assert (src/mongo/shell/assert.js:20:5)
at DB.shutdownServer (src/mongo/shell/db.js:212:9)
at (shell):1:4 at src/mongo/shell/assert.js:13
A:
gechongrepl:ARBITER> use admin
switched to db admin
gechongrepl:ARBITER> db.shutdownServer()
再次关闭P:
gechongrepl:PRIMARY> use admin
switched to db admin
2015-05-29T00:00:44.938-0700 I NETWORK DBClientCursor::init call() failed
2015-05-29T00:00:44.940-0700 I NETWORK trying reconnect to 127.0.0.1:27017 (127.0.0.1) failed
2015-05-29T00:00:44.941-0700 I NETWORK reconnect 127.0.0.1:27017 (127.0.0.1) ok
gechongrepl:SECONDARY> db.shutdownServer()
5:关闭顺序APS
A:
gechongrepl:ARBITER> use admin
switched to db admin
gechongrepl:ARBITER> db.shutdownServer()
P:
gechongrepl:PRIMARY> use admin
switched to db admin
gechongrepl:PRIMARY> db.shutdownServer()
S:因为仲裁节点关闭了。所以Primary节点不会再自动切换
gechongrepl:SECONDARY> use admin
switched to db admin
gechongrepl:SECONDARY> db.shutdownServer()
6:关闭顺序ASP
A:
gechongrepl:ARBITER> use admin
switched to db admin
gechongrepl:ARBITER> db.shutdownServer()
S:
gechongrepl:SECONDARY> use admin
switched to db admin
gechongrepl:SECONDARY> db.shutdownServer()
P:
gechongrepl:PRIMARY>
2015-05-29T00:12:23.962-0700 I NETWORK DBClientCursor::init call() failed
2015-05-29T00:12:23.965-0700 I NETWORK trying reconnect to 127.0.0.1:27017 (127.0.0.1) failed
2015-05-29T00:12:23.966-0700 I NETWORK reconnect 127.0.0.1:27017 (127.0.0.1) ok
Primary变为Secondary:
gechongrepl:SECONDARY>
gechongrepl:SECONDARY> use admin
switched to db admin
gechongrepl:SECONDARY> db.shutdownServer()
总结:
1:先关闭从节点、仲裁节点。或者先关闭仲裁节点,最后关闭从节点。则:主节点自动变为从节点
2:先关闭主节点,则从节点自动变为主节点,在仲裁节点关闭之前,新主节点不能关闭
初始化的时候主从节点受priority的影响
priority: 是优先级,默认为1,优先级0为被动节点,不能成为活跃节点。优先级不位0则按照有大到小选出活跃节点。