在GBase 8a的centos 8版本安装时，偶发卡住，查看后发现是一个简单的ssh命令没有返回，经排查发现，在centos 8里，其自带了几个yum源，导致运行某些不存在的命令时，会【推荐】安装rpm包，导致卡住。
目录导航
表现
GBase 8a安装时卡住
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Do you accept the above licence agreement ([Y,y]/[N,n])? y
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Welcome to install GBase products
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Environmental Checking on gcluster nodes.查看代码，在ssh远程执行如下代码时
"export LANG=C; ret=`lssubsys -a`; echo $?分析
手工执行不存在的命令出现推荐安装rpm
发现如下的输出
[root@redhat8_3 ~]# lssubsys -a
bash: lssubsys: command not found...
Install package 'libcgroup-tools' to provide command 'lssubsys'? [N/y]除了打印出command not found之外，还额外出现了推荐安装rpm包的选择[Y/N]，正是这个交互式输入，导致远程命令无法继续，从而卡住。
排查推荐的原因
经分析，在linux里对command not found的处理，有一个工具PackageKit.sh， 处理了command_not_found_handle
[root@redhat8_3 profile.d]# cat /etc/profile.d/PackageKit.sh
# Copyright (C) 2008 Richard Hughes <richard@hughsie.com>
#
# Licensed under the GNU General Public License Version 2
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
command_not_found_handle () {
local runcnf=1
local retval=127
# only search for the command if we're interactive
[[ $- == *"i"* ]] || runcnf=0
# don't run if DBus isn't running
[[ ! -S /run/dbus/system_bus_socket ]] && runcnf=0
# don't run if packagekitd doesn't exist in the _system_ root
[[ ! -x '/usr/libexec/packagekitd' ]] && runcnf=0
# don't run if bash command completion is being run
[[ -n ${COMP_CWORD-} ]] && runcnf=0
# don't run if we've been uninstalled since the shell was launched
[[ ! -x '/usr/libexec/pk-command-not-found' ]] && runcnf=0
# run the command, or just print a warning
if [ $runcnf -eq 1 ]; then
'/usr/libexec/pk-command-not-found' "$@"
retval=$?
elif [[ -n "${BASH_VERSION-}" ]]; then
printf >&2 'bash: %scommand not found\n' "${1:+$1: }"
fi
# return success or failure
return $retval
}
if [[ -n "${ZSH_VERSION-}" ]]; then
command_not_found_handler () {
command_not_found_handle "$@" && return 127
}
fi
内部会调用command_not_found_handle命令，该命令对应的程序是 /usr/libexec/pk-command-not-found，查看进程，发现了lssubsys的命令
[root@redhat8_3 ~]# ps -ef | grep lssub
root 56417 56416 0 Jan20 pts/7 00:00:00 /usr/libexec/pk-command-not-found lssubsys -a
root 60747 21328 0 00:00 pts/6 00:00:00 grep --color=auto lssub排查推荐的安装包来自哪里
查看yum数据源，发现有enable的
[root@redhat8_3 profile.d]# yum repolist all
repo id repo name status
appstream CentOS Linux 8 - AppStream enabled
appstream-source CentOS Linux 8 - AppStream - Source disabled
baseos CentOS Linux 8 - BaseOS enabled
baseos-source CentOS Linux 8 - BaseOS - Source disabled
cr CentOS Linux 8 - ContinuousRelease disabled
debuginfo CentOS Linux 8 - Debuginfo disabled
devel CentOS Linux 8 - Devel WARNING! FOR BUILDROOT USE ONLY! disabled
extras CentOS Linux 8 - Extras enabled
extras-source CentOS Linux 8 - Extras - Source disabled
fasttrack CentOS Linux 8 - FastTrack disabled
ha CentOS Linux 8 - HighAvailability disabled
media-appstream CentOS Linux 8 - Media - AppStream disabled
media-baseos CentOS Linux 8 - Media - BaseOS disabled
plus CentOS Linux 8 - Plus disabled
plus-source CentOS Linux 8 - Plus - Source disabled
powertools CentOS Linux 8 - PowerTools disabled
[root@redhat8_3 profile.d]#这些数据源配置在/etc/yum.repos.d/下面
[root@redhat8_3 profile.d]# cd /etc/yum.repos.d/
[root@redhat8_3 yum.repos.d]# ll
total 48
-rw-r--r--. 1 root root 719 Nov 9 2020 CentOS-Linux-AppStream.repo
-rw-r--r--. 1 root root 704 Nov 9 2020 CentOS-Linux-BaseOS.repo
-rw-r--r--. 1 root root 1130 Nov 9 2020 CentOS-Linux-ContinuousRelease.repo
-rw-r--r--. 1 root root 318 Nov 9 2020 CentOS-Linux-Debuginfo.repo
-rw-r--r--. 1 root root 732 Nov 9 2020 CentOS-Linux-Devel.repo
-rw-r--r--. 1 root root 704 Nov 9 2020 CentOS-Linux-Extras.repo
-rw-r--r--. 1 root root 719 Nov 9 2020 CentOS-Linux-FastTrack.repo
-rw-r--r--. 1 root root 740 Nov 9 2020 CentOS-Linux-HighAvailability.repo
-rw-r--r--. 1 root root 693 Nov 9 2020 CentOS-Linux-Media.repo
-rw-r--r--. 1 root root 706 Nov 9 2020 CentOS-Linux-Plus.repo
-rw-r--r--. 1 root root 724 Nov 9 2020 CentOS-Linux-PowerTools.repo
-rw-r--r--. 1 root root 898 Nov 9 2020 CentOS-Linux-Sources.repo关闭yum数据源
修改对应的配置文件，将其中的enable=1改成enable=0
[root@redhat8_3 yum.repos.d]# cat CentOS-Linux-AppStream.repo
# CentOS-Linux-AppStream.repo
#
# The mirrorlist system uses the connecting IP address of the client and the
# update status of each mirror to pick current mirrors that are geographically
# close to the client. You should use this for CentOS updates unless you are
# manually picking other mirrors.
#
# If the mirrorlist does not work for you, you can try the commented out
# baseurl line instead.
[appstream]
name=CentOS Linux $releasever - AppStream
mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=AppStream&infra=$infra
#baseurl=http://mirror.centos.org/$contentdir/$releasever/AppStream/$basearch/os/
gpgcheck=1
enabled=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-centosofficial
[root@redhat8_3 yum.repos.d]# vi CentOS-Linux-AppStream.repo
[root@redhat8_3 yum.repos.d]# cat CentOS-Linux-AppStream.repo
# CentOS-Linux-AppStream.repo
#
# The mirrorlist system uses the connecting IP address of the client and the
# update status of each mirror to pick current mirrors that are geographically
# close to the client. You should use this for CentOS updates unless you are
# manually picking other mirrors.
#
# If the mirrorlist does not work for you, you can try the commented out
# baseurl line instead.
[appstream]
name=CentOS Linux $releasever - AppStream
mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=AppStream&infra=$infra
#baseurl=http://mirror.centos.org/$contentdir/$releasever/AppStream/$basearch/os/
gpgcheck=1
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-centosofficial
[root@redhat8_3 yum.repos.d]#其它几个都关掉，我本地测试只关掉了前2个，那个extra我没关。
[root@redhat8_3 yum.repos.d]# yum repolist all
repo id repo name status
appstream CentOS Linux 8 - AppStream disabled
appstream-source CentOS Linux 8 - AppStream - Source disabled
baseos CentOS Linux 8 - BaseOS disabled
baseos-source CentOS Linux 8 - BaseOS - Source disabled
cr CentOS Linux 8 - ContinuousRelease disabled
debuginfo CentOS Linux 8 - Debuginfo disabled
devel CentOS Linux 8 - Devel WARNING! FOR BUILDROOT USE ONLY! disabled
extras CentOS Linux 8 - Extras enabled
extras-source CentOS Linux 8 - Extras - Source disabled
fasttrack CentOS Linux 8 - FastTrack disabled
ha CentOS Linux 8 - HighAvailability disabled
media-appstream CentOS Linux 8 - Media - AppStream disabled
media-baseos CentOS Linux 8 - Media - BaseOS disabled
plus CentOS Linux 8 - Plus disabled
plus-source CentOS Linux 8 - Plus - Source disabled
powertools CentOS Linux 8 - PowerTools disabled
[root@redhat8_3 yum.repos.d]#
验证命令是否不再出现推荐安装
再次运行，发现只报错command no found，不再出现推荐安装的选项了。
[root@redhat8_3 ~]# lssubsys -a
bash: lssubsys: command not found...
[root@redhat8_3 ~]#
尝试安装集群
正常安装，没有卡住。
*********************************************************************************
Do you accept the above licence agreement ([Y,y]/[N,n])? y
*********************************************************************************
Welcome to install GBase products
*********************************************************************************
Environmental Checking on gcluster nodes.
Cgconfig service is not exist on host ['10.0.2.181'], resource manangement can not be used, continue ([Y,y]/[N,n])? n
总结
linux的PackageKit工具，对不存在的命令进行了人性化推荐，导致远程运行不存在的命令时出现了推荐安装的选项，而调用方并没有处理这种情况，导致一直带等待客户输入，从而卡住。
解决方案
- 等待新版本
- 暂时关闭yum数据源(临时措施)
- 手工安装上依赖的命令包(临时措施)