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 <<EOF >/etc/yum.repos.d/upgradetool.repo
[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
EOF2.2 安装升级工具
yum install redhat-upgrade-tool preupgrade-assistant preupgrade-assistant-contents -y2.3 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-72.5 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
转载于:https://blog.51cto.com/moerjinrong/2340656
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