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  • Wang 20:05 on 2018-01-22 Permalink | Reply
    Tags: , docker swarm, gist   

    Deploy apps with docker swarm 

    I received alert email that my website crushed down, after checking, I found mysql container is stoped..

    I checked system log, found infos as below:

    Jan 22 18:42:39 ip-172-31-28-84 kernel: Out of memory: Kill process 597 (mysqld) score 226 or sacrifice child
    Jan 22 18:42:39 ip-172-31-28-84 kernel: Killed process 597 (mysqld) total-vm:1128616kB, anon-rss:228980kB, file-rss:0kB, shmem-rss:0kB
    

    I think the process is killed by kernel for lack of memory, because the server only has 1GB memory ..

    [root@ip-172-31-28-84 log]# free -h
                  total        used        free      shared  buff/cache   available
    Mem:           990M        559M         83M        113M        348M        133M
    Swap:            0B          0B          0B
    

    I restarted mysql container, and check containers’s status:

    [root@ip-172-31-28-84 log]# docker stats --no-stream
    CONTAINER           CPU %               MEM USAGE / LIMIT     MEM %               NET I/O             BLOCK I/O           PIDS
    9e5a47485105        0.00%               28.66MiB / 990.8MiB   2.89%               90.9MB / 43.2MB     24.9MB / 0B         2
    c9187825cc0c        0.00%               273.8MiB / 990.8MiB   27.63%              3.95GB / 1.02GB     11GB / 2.58MB       11
    628e301d00a1        0.04%               217.9MiB / 990.8MiB   21.99%              10.4MB / 136MB      101MB / 363MB       31
    

    there is no limitation on resources, so mysql will occupy more memory which caused being killed.

    After thinking about this, I decided deploy by docker swarm which will start container if stoped, and also could restrict resources for every container.

    1.init docker swarm on single server

    docker swarm init
    

    2.modify blog-compose.yml to support swarm, please follow gist

    https://gist.githubusercontent.com/hongmengwang/c5ca0368f5de15a612972c4bb676d409/raw/d8d706bb42769f20506d00f01603f34686b4fac9/blog-compose.yml
    

    3.deploy service

    docker stack deploy -c blog-compose.yml blog
    

    4.check container status

    [root@ip-172-31-28-84 docker]# docker stack services blog
    ID                  NAME                MODE                REPLICAS            IMAGE               PORTS
    0l68syg6q1bi        blog_nginx          replicated          1/1                 nginx:1.13.8        *:80->80/tcp,*:443->443/tcp
    cx82xalbzdzu        blog_wordpress      replicated          1/1                 wordpress:4.9.1     
    xulj5sbkbapb        blog_mysql          replicated          1/1                 mysql:5.7           
    

    5.check container stats

    [root@ip-172-31-28-84 docker]# docker stats --no-stream
    CONTAINER           CPU %               MEM USAGE / LIMIT   MEM %               NET I/O             BLOCK I/O           PIDS
    08bc88c00f0c        0.04%               189.7MiB / 250MiB   75.86%              70.5kB / 1.02MB     14MB / 13.9MB       30
    64d37b150392        0.00%               29.02MiB / 50MiB    58.05%              12.6kB / 14.7kB     1.24MB / 0B         2
    f33ecf2c045e        0.00%               92.32MiB / 300MiB   30.77%              1.03MB / 76.8kB     27.8MB / 0B         9
    

    The memory of each container is restricted, it will not occupy more memory than limitation, I will keep on watching to see if works well.

     
  • Wang 22:09 on 2018-01-09 Permalink | Reply
    Tags: gist,   

    start writing with gist, https://gist.github.com/hongmengwang

     
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