CentOS6-x到CentOS7-x的在线升级

1 缘起

相比Debian系的Linux发布版(如Debian、Ubuntu),都能很好地支持在线大版本升级,RedHat系的Linux发布版(如RedHat、CentOS),其大版本升级一直是为人所诟病的问题。
这种情况到了CentOS7,终于有了改观:RedHat放出了UpgradeTool,同样,CentOS自然也有了。

注意:如果已经是CentOS6.7及以后的版本,在线升级到CentOS7可能会有问题,因为CentOS6.7以后版本有些软件的版本已经比CentOS7还高了,因此这些软件包无法正确升级。这会导致系统损坏,并且几个系统工具无法正常工作。您将无法登录或使用网络。那么升级到CentOS 7的唯一方法就是全新安装。

  • 请注意在升级之前请备份!

2 具体步骤

2.1 配置升级工具upgradetool源

cat>/etc/yum.repos.d/upgradetool.repo<<EOF
[upg]
name=CentOS-$releasever - Upgrade Tool
baseurl=http://dev.centos.org/centos/6/upg/x86_64/
gpgcheck=1
enabled=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
EOF

2.2 安装升级工具

yum install redhat-upgrade-tool preupgrade-assistant preupgrade-assistant-contents -y

2.3 升级前可行性分析

[root@node1 ~]# preupg -l               # 查看支持的升级
CentOS6_7
[root@node1 ~]# preupg -s CentOS6_7     # 执行升级分析
Preupg tool doesn't do the actual upgrade.
Please ensure you have backed up your system and/or data in the event of a failed upgrade
 that would require a full re-install of the system from installation media.
Do you want to continue? y/n            # y,同意
y
Gathering logs used by preupgrade assistant:
All installed packages : 01/11 ...finished (time 00:00s)
All changed files      : 02/11 ...finished (time 01:33s)
Changed config files   : 03/11 ...finished (time 00:00s)
All users              : 04/11 ...finished (time 00:00s)
All groups             : 05/11 ...finished (time 00:00s)
Service statuses       : 06/11 ...finished (time 00:00s)
All installed files    : 07/11 ...finished (time 00:01s)
All local files        : 08/11 ...finished (time 00:01s)
All executable files   : 09/11 ...finished (time 00:00s)
RedHat signed packages : 10/11 ...finished (time 00:00s)
CentOS signed packages : 11/11 ...finished (time 00:00s)
Assessment of the system, running checks / SCE scripts:
001/096 ...done    (Configuration Files to Review)
002/096 ...done    (File Lists for Manual Migration)
003/096 ...done    (Bacula Backup Software)
004/096 ...done    (MySQL configuration)
005/096 ...done    (Migration of the MySQL data stack)
006/096 ...done    (Changes related to moving from MySQL to MariaDB)
007/096 ...done    (PostgreSQL upgrade content)
008/096 ...done    (GNOME Desktop Environment underwent several design modifications in CentOS 7 release)
009/096 ...done    (KDE Desktop Environment underwent several design modifications in CentOS 7 release)
010/096 ...done    (several graphic drivers not supported in CentOS 7)
011/096 ...done    (several input drivers not supported in CentOS 7)
012/096 ...done    (several kernel networking drivers not available in CentOS 7)
013/096 ...done    (several kernel storage drivers not available in CentOS 7)
014/096 ...done    (Names, Options and Output Format Changes in arptables)
015/096 ...done    (BIND9 running in a chroot environment check.)
016/096 ...done    (BIND9 configuration compatibility check)
017/096 ...done    (Move dhcpd/dhcprelay arguments from /etc/sysconfig/* to *.service files)
018/096 ...done    (DNSMASQ configuration compatibility check)
019/096 ...done    (Dovecot configuration compatibility check)
020/096 ...done    (Compatibility Between iptables and ip6tables)
021/096 ...done    (Net-SNMP check)
022/096 ...done    (Squid configuration compatibility check)
023/096 ...done    (Reusable Configuration Files)
024/096 ...done    (VCS repositories)
025/096 ...done    (Added and extended options for BIND9 configuration)
026/096 ...done    (Added options in DNSMASQ configuration)
027/096 ...done    (Packages not signed by CentOS)
028/096 ...done    (Obsoleted rpms)
029/096 ...done    (w3m not available in CentOS 7)
030/096 ...done    (report incompatibilities between CentOS 6 and 7 in qemu-guest-agent package)
031/096 ...done    (Removed options in coreutils binaries)
032/096 ...done    (Removed options in gawk binaries)
033/096 ...done    (Removed options in netstat binary)
034/096 ...done    (Removed options in quota tools)
035/096 ...done    (Removed rpms)
036/096 ...done    (Replaced rpms)
037/096 ...done    (GMP library incompatibilities)
038/096 ...done    (package downgrades)
039/096 ...done    (restore custom selinux configuration)
040/096 ...done    (General)
041/096 ...done    (samba shared directories selinux)
042/096 ...done    (CUPS Browsing/BrowsePoll configuration)
043/096 ...done    (CVS Package Split)
044/096 ...done    (FreeRADIUS Upgrade Verification)
045/096 ...done    (httpd configuration compatibility check)
046/096 ...done    (bind-dyndb-ldap)
047/096 ...done    (Identity Management Server compatibility check)
048/096 ...done    (IPA Server CA Verification)
049/096 ...done    (NTP configuration)
050/096 ...done    (Information on time-sync.target)
051/096 ...done    (OpenLDAP /etc/sysconfig and data compatibility)
052/096 ...done    (OpenSSH sshd_config migration content)
053/096 ...done    (OpenSSH sysconfig migration content)
054/096 ...done    (Configuration for quota_nld service)
055/096 ...done    (Disk quota netlink message daemon moved into quota-nld package)
056/096 ...done    (SSSD compatibility check)
057/096 ...done    (Luks encrypted partition)
058/096 ...done    (Clvmd and cmirrord daemon management.)
059/096 ...done    (State of LVM2 services.)
060/096 ...done    (device-mapper-multipath configuration compatibility check)
061/096 ...done    (Removal of scsi-target-utils)
062/096 ...done    (Configuration for warnquota tool)
063/096 ...done    (Disk quota tool warnquota moved into quota-warnquota package)
064/096 ...done    (Architecture Support)
065/096 ...done    (Binary rebuilds)
066/096 ...done    (Debuginfo packages)
067/096 ...done    (Cluster and High Availability)
068/096 ...done    (Quorum implementation)
069/096 ...done    (fix krb5kdc config file)
070/096 ...done    (File Systems, Partitions and Mounts Configuration Review)
071/096 ...done    (Read Only FHS directories)
072/096 ...done    (Sonamebumped libs)
073/096 ...done    (SonameKept Reusable Dynamic Libraries)
074/096 ...done    (Removed .so libs)
075/096 ...done    (In-place Upgrade Requirements for the /usr/ Directory)
076/096 ...done    (CA certificate bundles modified)
077/096 ...done    (Developer Tool Set packages)
078/096 ...done    (Hyper-V)
079/096 ...done    (Content for enabling and disabling services based on CentOS 6 system)
080/096 ...done    (Check for ethernet interface naming)
081/096 ...done    (User modification in /etc/rc.local and /etc/rc.d/rc.local)
082/096 ...done    (cgroups configuration compatibility check)
083/096 ...done    (Plugable authentication modules (PAM))
084/096 ...done    (Foreign Perl modules)
085/096 ...done    (Python 2.7.5)
086/096 ...done    (Ruby 2.0.0)
087/096 ...done    (SCL collections)
088/096 ...done    (System kickstart)
089/096 ...done    (YUM)
090/096 ...done    (Check for usage of dangerous range of UID/GIDs)
091/096 ...done    (Incorrect usage of reserved UID/GIDs)
092/096 ...done    (NIS ypbind config files back-up)
093/096 ...done    (NIS Makefile back-up)
094/096 ...done    (NIS server maps check)
095/096 ...done    (NIS server MAXUID and MAXGID limits check)
096/096 ...done    (NIS server config file back-up)
Assessment finished (time 02:04s)
Result table with checks and their results for main contents:
---------------------------------------------------------------------------------------------------------------
|Bacula Backup Software                                                                    |notapplicable     |
|MySQL configuration                                                                       |notapplicable     |
|Migration of the MySQL data stack                                                         |notapplicable     |
|Changes related to moving from MySQL to MariaDB                                           |notapplicable     |
|PostgreSQL upgrade content                                                                |notapplicable     |
|GNOME Desktop Environment underwent several design modifications in CentOS 7 release      |notapplicable     |
|KDE Desktop Environment underwent several design modifications in CentOS 7 release        |notapplicable     |
|several graphic drivers not supported in CentOS 7                                         |notapplicable     |
|several input drivers not supported in CentOS 7                                           |notapplicable     |
|Names, Options and Output Format Changes in arptables                                     |notapplicable     |
|BIND9 running in a chroot environment check.                                              |notapplicable     |
|BIND9 configuration compatibility check                                                   |notapplicable     |
|Move dhcpd/dhcprelay arguments from /etc/sysconfig/* to *.service files                   |notapplicable     |
|DNSMASQ configuration compatibility check                                                 |notapplicable     |
|Dovecot configuration compatibility check                                                 |notapplicable     |
|Net-SNMP check                                                                            |notapplicable     |
|Squid configuration compatibility check                                                   |notapplicable     |
|Added and extended options for BIND9 configuration                                        |notapplicable     |
|Added options in DNSMASQ configuration                                                    |notapplicable     |
|w3m not available in CentOS 7                                                             |notapplicable     |
|report incompatibilities between CentOS 6 and 7 in qemu-guest-agent package               |notapplicable     |
|restore custom selinux configuration                                                      |notapplicable     |
|samba shared directories selinux                                                          |notapplicable     |
|CUPS Browsing/BrowsePoll configuration                                                    |notapplicable     |
|FreeRADIUS Upgrade Verification                                                           |notapplicable     |
|httpd configuration compatibility check                                                   |notapplicable     |
|bind-dyndb-ldap                                                                           |notapplicable     |
|Identity Management Server compatibility check                                            |notapplicable     |
|IPA Server CA Verification                                                                |notapplicable     |
|OpenLDAP /etc/sysconfig and data compatibility                                            |notapplicable     |
|SSSD compatibility check                                                                  |notapplicable     |
|Clvmd and cmirrord daemon management.                                                     |notapplicable     |
|device-mapper-multipath configuration compatibility check                                 |notapplicable     |
|Removal of scsi-target-utils                                                              |notapplicable     |
|Quorum implementation                                                                     |notapplicable     |
|fix krb5kdc config file                                                                   |notapplicable     |
|cgroups configuration compatibility check                                                 |notapplicable     |
|Ruby 2.0.0                                                                                |notapplicable     |
|NIS ypbind config files back-up                                                           |notapplicable     |
|NIS Makefile back-up                                                                      |notapplicable     |
|NIS server maps check                                                                     |notapplicable     |
|NIS server MAXUID and MAXGID limits check                                                 |notapplicable     |
|NIS server config file back-up                                                            |notapplicable     |
|several kernel networking drivers not available in CentOS 7                               |pass              |
|several kernel storage drivers not available in CentOS 7                                  |pass              |
|Compatibility Between iptables and ip6tables                                              |pass              |
|Reusable Configuration Files                                                              |pass              |
|NTP configuration                                                                         |pass              |
|Information on time-sync.target                                                           |pass              |
|OpenSSH sshd_config migration content                                                     |pass              |
|Configuration for quota_nld service                                                       |pass              |
|Disk quota netlink message daemon moved into quota-nld package                            |pass              |
|Luks encrypted partition                                                                  |pass              |
|Configuration for warnquota tool                                                          |pass              |
|Architecture Support                                                                      |pass              |
|Debuginfo packages                                                                        |pass              |
|Cluster and High Availability                                                             |pass              |
|Read Only FHS directories                                                                 |pass              |
|In-place Upgrade Requirements for the /usr/ Directory                                     |pass              |
|CA certificate bundles modified                                                           |pass              |
|Developer Tool Set packages                                                               |pass              |
|Hyper-V                                                                                   |pass              |
|Check for ethernet interface naming                                                       |pass              |
|Plugable authentication modules (PAM)                                                     |pass              |
|SCL collections                                                                           |pass              |
|System kickstart                                                                          |pass              |
|Check for usage of dangerous range of UID/GIDs                                            |pass              |
|Incorrect usage of reserved UID/GIDs                                                      |pass              |
|VCS repositories                                                                          |informational     |
|Removed options in coreutils binaries                                                     |informational     |
|Removed options in gawk binaries                                                          |informational     |
|Removed options in netstat binary                                                         |informational     |
|Removed options in quota tools                                                            |informational     |
|GMP library incompatibilities                                                             |informational     |
|CVS Package Split                                                                         |informational     |
|Disk quota tool warnquota moved into quota-warnquota package                              |informational     |
|File Systems, Partitions and Mounts Configuration Review                                  |informational     |
|Sonamebumped libs                                                                         |informational     |
|SonameKept Reusable Dynamic Libraries                                                     |informational     |
|Removed .so libs                                                                          |informational     |
|Foreign Perl modules                                                                      |informational     |
|YUM                                                                                       |informational     |
|Replaced rpms                                                                             |fixed             |
|package downgrades                                                                        |fixed             |
|OpenSSH sysconfig migration content                                                       |fixed             |
|State of LVM2 services.                                                                   |fixed             |
|Configuration Files to Review                                                             |needs_inspection  |
|File Lists for Manual Migration                                                           |needs_inspection  |
|Obsoleted rpms                                                                            |needs_inspection  |
|Binary rebuilds                                                                           |needs_inspection  |
|Python 2.7.5                                                                              |needs_inspection  |
|Packages not signed by CentOS                                                             |needs_action      |
|Removed rpms                                                                              |needs_action      |
|General                                                                                   |needs_action      |
|Content for enabling and disabling services based on CentOS 6 system                      |needs_action      |
|User modification in /etc/rc.local and /etc/rc.d/rc.local                                 |needs_action      |
---------------------------------------------------------------------------------------------------------------
Tarball with results is stored here /root/preupgrade-results/preupg_results-190109142717.tar.gz .
The latest assessment is stored in directory /root/preupgrade .
Summary information:
We found some potential in-place upgrade risks.
Read the file /root/preupgrade/result.html for more details.
Upload results to UI by command:
e.g. preupg -u http://127.0.0.1:8099/submit/ -r /root/preupgrade-results/preupg_results-*.tar.gz .
[root@node1 ~]#

直到完成(跑相当长的时间,请耐心等待)

preupg: error: [Errno 2] No such file or directory: '/root/preupgrade/result.html'

如果报上面这个错误:重新装旧版本的openscp

yum erase openscap
yum install http://dev.centos.org/centos/6/upg/x86_64/Packages/openscap-1.0.8-1.0.1.el6.centos.x86_64.rpm
yum install redhat-upgrade-tool preupgrade-assistant-contents

没有提示出错,可以继续下一步。否则请检查!!!要全部PASS才可以。

上面这个命令生成的报告需要看看,主要是关于升级的风险的
个人经验就是升级前尽量将非官方的rpm安装的软件都删掉
安装的第三方的rpm包越少,升级的风险越小

2.4 导入centos7源

官方源:

rpm --import http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-7

阿里源:

rpm --import https://mirrors.aliyun.com/centos/7/os/x86_64/RPM-GPG-KEY-CentOS-7

2.5 升级系统

官方源:

centos-upgrade-tool-cli --network 7 --instrepo=http://mirror.centos.org/centos/7/os/x86_64/

阿里源:

centos-upgrade-tool-cli --network 7 --instrepo=https://mirrors.aliyun.com/centos/7/os/x86_64/

需要注意的是,这个镜像目录下需要有文件.treeinfo
没有的话就去官方的位置拷贝一个下来,记得版本号要一致;

这里不可以导入最新的,因为最新版的.treeinfo中没有upgrade项了,所以这里导入7.2的。

rpm --import http://vault.centos.org/centos/7.2.1511/os/x86_64/RPM-GPG-KEY-CentOS-7
centos-upgrade-tool-cli --network 7 --instrepo=http://vault.centos.org/centos/7.2.1511/os/x86_64/

2.6 重启服务器

reboot; 

3 收尾工作

机器起来后,登上服务器,需要做一些擦屁股的工作,比如,看还有没有CentOS6的软件残余,用命令:

rpm -qa | grep -i el6;

有的话要么想办法删掉,要么想办法将其升级到el7的相应的软件包。

4 参考

官方升级教程:CentOSUpgradeTool