MongoDB副本集配置系列四：节点的关闭顺序

接上一篇博客：http://www.cnblogs.com/xiaoit/p/4522218.html

Primary Secondary Arbiter
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

　　

1：关闭顺序PSA

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
}

　　

P：

gechongrepl:PRIMARY> use admin
switched to db admin
gechongrepl:PRIMARY> db.shutdownServer()

S:

从变为了：gechongrepl:PRIMARY>

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()

　　

　　

再次关闭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()

　　

下面猜测：在关闭最后的Primary节点之前，先关掉仲裁节点即不会报错。（首先关掉Primary节点，还有其他Secondary不属于这种情况）

5：关闭顺序APS ： 不会报错
6：关闭顺序ASP ： 不会报错

验证猜测：

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
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。