Docker安装PostgreSQL重启后/run/postgresql/*丢失问题

绝地灬酷狼 2023-06-08 09:27 10阅读 0赞

创建Docker并安装PostgreSQL

#创建docker
    docker run --privileged -dit --name test --net staticnet --ip 192.168.2.6 centos-ssh /usr/sbin/init
    #安装postgressql11.2
    yum install -y https://download.postgresql.org/pub/repos/yum/11/redhat/rhel-7-x86_64/pgdg-centos11-11-2.noarch.rpm
    yum install -y postgresql11 postgresql11-server
    #初始化data
    /usr/pgsql-11/bin/postgresql-11-setup initdb
    #设置开机自启并启动
    systemctl enable postgresql-11
    systemctl start postgresql-11

查看/run/postgresql

[root@06b0e1e15b1b run]# pwd
    /run
    [root@06b0e1e15b1b run]# ll
    total 16
    -rw-r--r--  1 root     root       3 Oct 17 17:06 atd.pid
    drwxr-xr-x  2 root     root      40 Oct 17 17:11 console
    -rw-r--r--  1 root     root       3 Oct 17 17:06 crond.pid
    ----------  1 root     root       0 Oct 17 17:06 cron.reboot
    drwx------  2 root     root      40 Oct 17 17:11 cryptsetup
    drwxr-xr-x  2 root     root      60 Oct 17 17:06 dbus
    drwxr-xr-x  2 root     root      40 Oct 17 17:11 faillock
    drwxr-xr-x  4 root     root      80 Oct 17 17:11 lock
    drwxr-xr-x  2 root     root      40 Oct 17 17:11 log
    drwxr-xr-x  2 root     root      40 Oct 17 17:06 mount
    drwxrwxr-x  2 root     root      40 Oct 17 17:11 netreport
    drwxr-xr-x  2 postgres postgres  40 Oct 17 17:17 postgresql
    drwxr-xr-x  2 root     root       6 Oct 17 17:06 secrets
    drwxr-xr-x  2 root     root      40 Oct 17 17:11 sepermit
    drwxr-xr-x  2 root     root      40 Oct 17 17:11 setrans
    -rw-r--r--  1 root     root       3 Oct 17 17:06 sshd.pid
    drwx--x--x  3 root     root      60 Oct 17 17:11 sudo
    drwx------  2 root     root      40 Oct 17 17:11 svnserve
    -rw-------  1 root     root       2 Oct 17 17:06 syslogd.pid
    drwxr-xr-x 15 root     root     400 Oct 17 17:15 systemd
    drwxr-xr-x  2 root     root      40 Oct 17 17:11 user
    [root@06b0e1e15b1b run]# ll postgresql/ -a
    total 4
    drwxr-xr-x  2 postgres postgres  80 Oct 17 17:31 .
    drwxr-xr-x 18 root     root     460 Oct 17 17:17 ..
    srwxrwxrwx  1 postgres postgres   0 Oct 17 17:31 .s.PGSQL.5432
    -rw-------  1 postgres postgres  63 Oct 17 17:31 .s.PGSQL.5432.lock

可以看到`/run/postgresql`中包含`.s.PGSQL.5432`和`.s.PGSQL.5432.lock`

重启docker容器

docker restart test

进入容器查看

[root@Server]# docker exec -ti test /bin/bash
    [root@06b0e1e15b1b /]# cd /run/
    [root@06b0e1e15b1b run]# ll
    total 16
    -rw-r--r-- 1 root root   3 Oct 17 17:34 atd.pid
    -rw-r--r-- 1 root root   3 Oct 17 17:34 crond.pid
    ---------- 1 root root   0 Oct 17 17:34 cron.reboot
    drwxr-xr-x 2 root root  60 Oct 17 17:34 dbus
    drwxr-xr-x 2 root root  40 Oct 17 17:34 lock
    drwxr-xr-x 2 root root  40 Oct 17 17:34 mount
    drwxr-xr-x 2 root root   6 Oct 17 17:34 secrets
    -rw-r--r-- 1 root root   3 Oct 17 17:34 sshd.pid
    -rw------- 1 root root   2 Oct 17 17:34 syslogd.pid
    drwxr-xr-x 8 root root 260 Oct 17 17:34 systemd

重启后会发现`/run/postgresql`丢失了

### 问题分析： ###

执行`df`

[root@06b0e1e15b1b run]# df
    Filesystem     1K-blocks     Used Available Use% Mounted on
    overlay         41931776 12979836  28951940  31% /
    tmpfs            4005220        0   4005220   0% /dev
    /dev/vda1       41931776 12979836  28951940  31% /etc/hosts
    shm                65536        0     65536   0% /dev/shm
    tmpfs              65536       24     65512   1% /run
    tmpfs              65536        0     65536   0% /run/lock
    tmpfs              65536        0     65536   0% /var/log/journal
    tmpfs            4005220        0   4005220   0% /tmp

发现第7行，/run使用的是tmpfs文件系统，简单来说就是一个基于内存的文件系统，断电重启后系统中的文件不会保存。详见：[tmpfs][]

### 解决方法： ###

#### 1.可以手动创建该目录并修改权限 ####

mkdir /run/postgresql
    chown -R postgres:postgres postgresql/

#### 2.可以通过systemd-tmpfiles来创建 ####

systemd-tmpfiles --create  /usr/lib/tmpfiles.d/*

因为`/run`目录的这个特殊性，CentOS7特意在`/usr/lib/tmpfiles.d/`下提供了可以自定义.conf的方式来解决这个问题。详见：[tmpfiles.d][]

[root@06b0e1e15b1b run]# cat /usr/lib/tmpfiles.d/postgresql-11.conf 
    d /run/postgresql 0755 postgres postgres -

PG为我们提供了这个配置文件，这行的意思就是有`/run/postgresql`就直接设置权限，没有就创建后再设置权限，这个指令在安装PG的时候会执行，因为安装时一般都在root权限下，而执行`systemctl start postgresql-11`时实际是用`/usr/pgsql-11/bin/postmaster -D ${PGDATA}`来启动，且使用postgres用户组和用户，导致无法创建该文件夹。而且执行`systemctl start postgresql-11`看不到任何报错，PG的log中也没有错误日志。只有再切换到postgres用户下执行`pg_ctl start`才会看到错误，报了`Permission denied`。

bash-4.2$ /usr/pgsql-11/bin/pg_ctl start -D /var/lib/pgsql/11/data
    waiting for server to start....2019-10-16 21:21:33.801 CST [277] LOG:  number of prepared transactions has not been configured, overriding
    2019-10-16 21:21:33.801 CST [277] DETAIL:  max_prepared_transactions is now set to 200
    2019-10-16 21:21:33.802 CST [277] LOG:  listening on IPv4 address "0.0.0.0", port 5432
    2019-10-16 21:21:33.802 CST [277] LOG:  listening on IPv6 address "::", port 5432
    2019-10-16 21:21:33.805 CST [277] FATAL:  could not create lock file "/var/run/postgresql/.s.PGSQL.5432.lock": Permission denied
    2019-10-16 21:21:33.805 CST [277] LOG:  database system is shut down
     stopped waiting
    pg_ctl: could not start server
    Examine the log output.

#### 3.修复`systemd-tmpfiles`服务 ####

`systemd-tmpfiles`服务是可以开机自启的，为什么在docker中就是有问题的，不能执行呢？

[root@06b0e1e15b1b run]# cat /usr/lib/systemd/system/systemd-tmpfiles-setup.service 
    # This file is part of systemd.
    #
    # systemd is free software; you can redistribute it and/or modify it
    # under the terms of the GNU Lesser General Public License as published by
    # the Free Software Foundation; either version 2.1 of the License, or
    # (at your option) any later version.
    
    [Unit]
    Description=Create Volatile Files and Directories
    Documentation=man:tmpfiles.d(5) man:systemd-tmpfiles(8)
    DefaultDependencies=no
    Conflicts=shutdown.target
    After=systemd-readahead-collect.service systemd-readahead-replay.service local-fs.target systemd-sysusers.service
    Before=sysinit.target shutdown.target
    RefuseManualStop=yes
    
    [Service]
    Type=oneshot
    RemainAfterExit=yes
    ExecStart=/usr/bin/systemd-tmpfiles --create --remove --boot --exclude-prefix=/dev

可以看到`systemd-tmpfiles-setup.service`中的`ExecStart`正是我们要执行的命令，通过执行`systemctl start systemd-tmpfiles-setup.service`看下结果

[root@06b0e1e15b1b systemd]# systemctl start systemd-tmpfiles-setup.service
    Failed to start systemd-tmpfiles-setup.service: Unit is masked.
    [root@06b0e1e15b1b systemd]# systemctl unmask systemd-tmpfiles-setup.service
    Removed symlink /etc/systemd/system/systemd-tmpfiles-setup.service.
    [root@06b0e1e15b1b systemd]# systemctl start systemd-tmpfiles-setup.service

会发现报`Unit is masked`，执行`ummask`后发现服务可以正常start，再次重起发现问题解决。

[tmpfs]: https://www.jb51.net/LINUXjishu/342876.html
[tmpfiles.d]: http://www.jinbuguo.com/systemd/tmpfiles.d.html