问题描述:
今天在做saltstack的练习，想要通过sls的方式，在远程进行mysql数据库的安装，发现无法通过service的方式启动数据库，然后就想给删除了重新进行安装，在通过rpm -e进行删除rpm包时，报下面的错误：
[root@testvm03 ~]# rpm -e mysql-server-5.1.73-8.el6_8.x86_64 error reading information on service mysqld: Invalid argument error: %preun(mysql-server-5.1.73-8.el6_8.x86_64) scriptlet failed, exit status 1
问题分析：
开始对于这个报错，以为是rpm本身在删除软件的时候的报错，所以呢，就把错误贴到各种地方去搜索，搜索了很久也没有得到答案。后来想想，不对，我得仔细看看报错信息想要说明什么内容，然后看到第1行，明显是在读mysqld这个服务的信息报错，在思考，rpm -e的过程，首先应该是读取这个服务的状态，如果在运行，先将服务停掉，然后再进行删除各种相关文件的操作。
问题解决：
1.看看mysqld这个脚本是否存在，或者有问题
[root@testvm03 init.d]# ls -ltr total 224 -rwxr-xr-x. 1 root root 2898 Mar 20 2010 rhnsd -rwxr-xr-x 1 root root 2073 Oct 23 2012 rpcbind -rwxr-xr-x. 1 root root 2011 Aug 15 2013 rsyslog -rwxr-xr-x. 1 root root 2826 Sep 12 2013 crond -rwxr-xr-x. 1 root root 1513 Sep 17 2013 rdisc -rwxr-xr-x. 1 root root 3912 Feb 14 2014 postfix -rwxr-xr-x. 1 root root 2056 Jun 23 2014 saslauthd -rwxr-xr-x. 1 root root 647 Jul 22 2014 single -rwxr-xr-x. 1 root root 6334 Jul 22 2014 network -rwxr-xr-x. 1 root root 6064 Jul 22 2014 netfs -rwxr-xr-x. 1 root root 2989 Jul 22 2014 netconsole -rwxr-xr-x. 1 root root 652 Jul 22 2014 killall -rwxr-xr-x. 1 root root 5866 Jul 22 2014 halt -rw-r--r--. 1 root root 19295 Jul 22 2014 functions -rwxr-xr-x. 1 root root 2294 Jul 24 2014 udev-post -rwxr-xr-x. 1 root root 1698 Aug 9 2014 sandbox -rwxr-xr-x. 1 root root 1822 Aug 9 2014 restorecond -rwxr-xr-x. 1 root root 3580 Aug 10 2014 auditd -rwxr-xr-x. 1 root root 19476 Aug 27 2014 kdump -rwxr-xr-x. 1 root root 4621 Aug 27 2014 sshd -rwxr-xr-x. 1 root root 10688 Aug 28 2014 iptables -rwxr-xr-x. 1 root root 10804 Aug 28 2014 ip6tables -rwxr-xr-x. 1 root root 1738 Aug 29 2014 snmptrapd -rwxr-xr-x. 1 root root 2162 Aug 29 2014 snmpd -r-xr-xr-x. 1 root root 1340 Sep 1 2014 blk-availability -r-xr-xr-x. 1 root root 2757 Sep 1 2014 lvm2-monitor -r-xr-xr-x. 1 root root 2134 Sep 1 2014 lvm2-lvmetad -rwxr-xr-x 1 root root 2464 Sep 5 2014 rpcsvcgssd -rwxr-xr-x 1 root root 2305 Sep 5 2014 rpcidmapd -rwxr-xr-x 1 root root 2518 Sep 5 2014 rpcgssd -rwxr-xr-x 1 root root 3526 Sep 5 2014 nfslock -rwxr-xr-x 1 root root 6878 Sep 5 2014 nfs -rwxr-xr-x. 1 root root 2571 Sep 5 2014 mdmonitor -rwxr-xr-x. 1 root root 1215 Sep 16 2014 rhsmcertd -rwxr-xr-x 1 root root 0 Jan 27 2017 mysqld #经过检查，发现mysqld中的脚本是空字节的，就是没有任何的内容，如果要查mysqld的状态，传参自然是不可用的 -rwxr-xr-x 1 root root 3488 Jun 19 2018 httpd -rwxr-xr-x 1 root root 2001 Jun 19 2018 htcacheclean -rwxr-xr-x. 1 root root 1193 Jul 31 2018 nrpe -rwxr-xr-x 1 root root 7752 Feb 21 06:06 salt-minion
备注：这个也就能够解释执行service mysqld start为啥没有任何反应，脚本中啥都没有，mysqld根本不知道做什么。
2.考虑将其他机器上的mysqld脚本拷贝到/etc/init.d/目录下
[root@testvm03 init.d]# rm mysqld #删除空字节的mysqld脚本文件 rm: remove regular empty file `mysqld'? y [root@testvm03 init.d]# rz #通过rz命令，将其他主机上可用的脚本上传到此 [root@testvm03 init.d]# [root@testvm03 init.d]# ls -ltr total 232 -rwxr-xr-x. 1 root root 2898 Mar 20 2010 rhnsd -rwxr-xr-x 1 root root 2073 Oct 23 2012 rpcbind -rwxr-xr-x. 1 root root 2011 Aug 15 2013 rsyslog -rwxr-xr-x. 1 root root 2826 Sep 12 2013 crond -rwxr-xr-x. 1 root root 1513 Sep 17 2013 rdisc -rwxr-xr-x. 1 root root 3912 Feb 14 2014 postfix -rwxr-xr-x. 1 root root 2056 Jun 23 2014 saslauthd -rwxr-xr-x. 1 root root 647 Jul 22 2014 single -rwxr-xr-x. 1 root root 6334 Jul 22 2014 network -rwxr-xr-x. 1 root root 6064 Jul 22 2014 netfs -rwxr-xr-x. 1 root root 2989 Jul 22 2014 netconsole -rwxr-xr-x. 1 root root 652 Jul 22 2014 killall -rwxr-xr-x. 1 root root 5866 Jul 22 2014 halt -rw-r--r--. 1 root root 19295 Jul 22 2014 functions -rwxr-xr-x. 1 root root 2294 Jul 24 2014 udev-post -rwxr-xr-x. 1 root root 1698 Aug 9 2014 sandbox -rwxr-xr-x. 1 root root 1822 Aug 9 2014 restorecond -rwxr-xr-x. 1 root root 3580 Aug 10 2014 auditd -rwxr-xr-x. 1 root root 19476 Aug 27 2014 kdump -rwxr-xr-x. 1 root root 4621 Aug 27 2014 sshd -rwxr-xr-x. 1 root root 10688 Aug 28 2014 iptables -rwxr-xr-x. 1 root root 10804 Aug 28 2014 ip6tables -rwxr-xr-x. 1 root root 1738 Aug 29 2014 snmptrapd -rwxr-xr-x. 1 root root 2162 Aug 29 2014 snmpd -r-xr-xr-x. 1 root root 1340 Sep 1 2014 blk-availability -r-xr-xr-x. 1 root root 2757 Sep 1 2014 lvm2-monitor -r-xr-xr-x. 1 root root 2134 Sep 1 2014 lvm2-lvmetad -rwxr-xr-x 1 root root 2464 Sep 5 2014 rpcsvcgssd -rwxr-xr-x 1 root root 2305 Sep 5 2014 rpcidmapd -rwxr-xr-x 1 root root 2518 Sep 5 2014 rpcgssd -rwxr-xr-x 1 root root 3526 Sep 5 2014 nfslock -rwxr-xr-x 1 root root 6878 Sep 5 2014 nfs -rwxr-xr-x. 1 root root 2571 Sep 5 2014 mdmonitor -rwxr-xr-x. 1 root root 1215 Sep 16 2014 rhsmcertd -rw-r--r-- 1 root root 7026 Jan 27 2017 mysqld #有内容，没有执行权限 -rwxr-xr-x 1 root root 3488 Jun 19 2018 httpd -rwxr-xr-x 1 root root 2001 Jun 19 2018 htcacheclean -rwxr-xr-x. 1 root root 1193 Jul 31 2018 nrpe -rwxr-xr-x 1 root root 7752 Feb 21 06:06 salt-minion [root@testvm03 init.d]# chmod +x mysqld #增加该脚本的可执行权限
[root@testvm03 init.d]# ls -ltr
total 232
-rwxr-xr-x. 1 root root 2898 Mar 20 2010 rhnsd
-rwxr-xr-x 1 root root 2073 Oct 23 2012 rpcbind
-rwxr-xr-x. 1 root root 2011 Aug 15 2013 rsyslog
-rwxr-xr-x. 1 root root 2826 Sep 12 2013 crond
-rwxr-xr-x. 1 root root 1513 Sep 17 2013 rdisc
-rwxr-xr-x. 1 root root 3912 Feb 14 2014 postfix
-rwxr-xr-x. 1 root root 2056 Jun 23 2014 saslauthd
-rwxr-xr-x. 1 root root 647 Jul 22 2014 single
-rwxr-xr-x. 1 root root 6334 Jul 22 2014 network
-rwxr-xr-x. 1 root root 6064 Jul 22 2014 netfs
-rwxr-xr-x. 1 root root 2989 Jul 22 2014 netconsole
-rwxr-xr-x. 1 root root 652 Jul 22 2014 killall
-rwxr-xr-x. 1 root root 5866 Jul 22 2014 halt
-rw-r--r--. 1 root root 19295 Jul 22 2014 functions
-rwxr-xr-x. 1 root root 2294 Jul 24 2014 udev-post
-rwxr-xr-x. 1 root root 1698 Aug 9 2014 sandbox
-rwxr-xr-x. 1 root root 1822 Aug 9 2014 restorecond
-rwxr-xr-x. 1 root root 3580 Aug 10 2014 auditd
-rwxr-xr-x. 1 root root 19476 Aug 27 2014 kdump
-rwxr-xr-x. 1 root root 4621 Aug 27 2014 sshd
-rwxr-xr-x. 1 root root 10688 Aug 28 2014 iptables
-rwxr-xr-x. 1 root root 10804 Aug 28 2014 ip6tables
-rwxr-xr-x. 1 root root 1738 Aug 29 2014 snmptrapd
-rwxr-xr-x. 1 root root 2162 Aug 29 2014 snmpd
-r-xr-xr-x. 1 root root 1340 Sep 1 2014 blk-availability
-r-xr-xr-x. 1 root root 2757 Sep 1 2014 lvm2-monitor
-r-xr-xr-x. 1 root root 2134 Sep 1 2014 lvm2-lvmetad
-rwxr-xr-x 1 root root 2464 Sep 5 2014 rpcsvcgssd
-rwxr-xr-x 1 root root 2305 Sep 5 2014 rpcidmapd
-rwxr-xr-x 1 root root 2518 Sep 5 2014 rpcgssd
-rwxr-xr-x 1 root root 3526 Sep 5 2014 nfslock
-rwxr-xr-x 1 root root 6878 Sep 5 2014 nfs
-rwxr-xr-x. 1 root root 2571 Sep 5 2014 mdmonitor
-rwxr-xr-x. 1 root root 1215 Sep 16 2014 rhsmcertd
-rwxr-xr-x 1 root root 7026 Jan 27 2017 mysqld
-rwxr-xr-x 1 root root 3488 Jun 19 2018 httpd
-rwxr-xr-x 1 root root 2001 Jun 19 2018 htcacheclean
-rwxr-xr-x. 1 root root 1193 Jul 31 2018 nrpe
-rwxr-xr-x 1 root root 7752 Feb 21 06:06 salt-minion
3.尝试启动服务，或者删除软件包
[root@testvm03 init.d]# service mysqld start #尝试启动mysql，发现有内容，虽然报错了。 Initializing MySQL database: [ OK ] MySQL Daemon failed to start. Starting mysqld: [FAILED] [root@testvm03 init.d]# ps -ef | grep mysql #没有启动成功，但是不是关注的焦点，焦点在于删除这个组件包 root 1441 1291 0 10:45 pts/0 00:00:00 grep mysql [root@testvm03 init.d]# tail -f /var/log/mysqld.log ^C [root@testvm03 init.d]# rpm -qa | grep mysql mysql-server-5.1.73-8.el6_8.x86_64 mysql-5.1.73-8.el6_8.x86_64 mysql-libs-5.1.73-8.el6_8.x86_64 [root@testvm03 init.d]# rpm -e mysql-server-5.1.73-8.el6_8.x86_64 #再次执行删除包操作，发现是能够删除掉的。 warning: /etc/logrotate.d/mysqld saved as /etc/logrotate.d/mysqld.rpmsave [root@testvm03 init.d]# rpm -qa | grep mysql mysql-5.1.73-8.el6_8.x86_64 mysql-libs-5.1.73-8.el6_8.x86_64 [root@testvm03 init.d]#
备注：该问题得到解决，mysql-server的软件包，已经成功删除。
小结：在这个问题解决之后，我思考了这么一个问题，当执行rpm -e来卸载一个软件包的时候，都做了些什么事情，找了好久，找到了如下的一些信息。
链接地址：http://ftp.rpm.org/max-rpm/ch-rpm-erase.html#S1-RPM-ERASE-WHAT-DOES-IT-DO
rpm -e — What Does it Do? The rpm -e command (--erase is equivalent) removes, or erases, one or more packages from the system. RPM performs a series of steps whenever it erases a package: It checks the RPM database to make sure that no other packages depend on the package being erased. It executes a pre-uninstall script (if one exists). #执行一个预先卸载脚本，比如，检查软件是否在运行，运行就将其停掉等等。%preun 就是预卸载脚本的意思。 It checks to see if any of the package's config files have been modified. If so, it saves copies of them. It reviews the RPM database to find every file listed as being part of the package, and if they do not belong to another package, deletes them. It executes a post-uninstall script (if one exists). It removes all traces of the package (and the files belonging to it) from the RPM database.
另外，我也对自己解决问题的思路进行了一个调整，当你在解决一个问题的时候，如果想要更好的解决问题，那么最好的方式，就是对于你要操作的东西，有个基本工作原理的理解。看似很慢的理解工作原理，花费时间来思考，实则在解决问题时，却变得更加的容易，而不仅仅是搜索，搜索，搜索。
文档创建时间：2019年3月8日14:39:04