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。