由于?centos官網(wǎng)將要停止對centos6的支持?導(dǎo)致下面連接不能訪問，網(wǎng)上大多用的下面的連接找了半天找了個能用的記錄下
http://dev.centos.org/centos/6/upg/x86_64/?×
CentOS 6升級至Centos7
1.查看下當(dāng)前的系統(tǒng)版本
cat /etc/redhat-release
2.配置更新源
vi /etc/yum.repos.d/upgrade.repo
[upgrade]name=upgrade
baseurl=https://buildlogs.centos.org/centos/6/upg/x86_64/
enable=1
gpgcheck=0
安裝更新助手
由于centos 6.5自帶的助手之一版本較高，所以需要卸載了裝個更老的：
yum erase openscap -y
yum install redhat-upgrade-tool preupgrade-assistant-contents -y
升級前檢查潛在問題
preupg -s CentOS6_7
在線更新,在線更新會比較慢。可以先下載好鏡像，進(jìn)行本地更新。
centos-upgrade-tool-cli --network 7 --instrepo=https://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7
本地更新。
cd /tmp
wget https://mirrors.aliyun.com/centos/7.6.1810/isos/x86_64/CentOS-7-x86_64-DVD-1810.iso
centos-upgrade-tool-cli --iso=/tmp/CentOS-7-x86_64-DVD-1810.iso
(如果有問題可以加--force參數(shù)，但生產(chǎn)環(huán)境不建議)
設(shè)置好之后，執(zhí)行重啟系統(tǒng), 重啟系統(tǒng)會進(jìn)入更新的操作
界面可以看到需要更新軟件包，有進(jìn)度條。此外有部分報錯也是正常，因為版本不同軟件路徑也不一樣
更新完成之后，進(jìn)入系統(tǒng)界面。再次查看版本確認(rèn)
I/O warning : failed to load external entity "/usr/share/openscap/xsl/security-guide.xsl"
compilation error: file /usr/share/preupgrade/xsl/preup.xsl line 40 element import
xsl:import : unable to load /usr/share/openscap/xsl/security-guide.xsl
I/O warning : failed to load external entity "/usr/share/openscap/xsl/oval-report.xsl"
compilation error: file /usr/share/preupgrade/xsl/preup.xsl line 41 element import
xsl:import : unable to load /usr/share/openscap/xsl/oval-report.xsl
I/O warning : failed to load external entity "/usr/share/openscap/xsl/sce-report.xsl"
compilation error: file /usr/share/preupgrade/xsl/preup.xsl line 42 element import
xsl:import : unable to load /usr/share/openscap/xsl/sce-report.xsl
OpenSCAP Error:: Could not parse XSLT file '/usr/share/preupgrade/xsl/preup.xsl' [oscapxml.c:416]
Unable to open file /root/preupgrade/result.html
Usage: preupg [options]
preupg: error: [Errno 2] No such file or directory: '/root/preupgrade/result.html'
遇到問題那么就找原因和解決方法，通過搜索引擎搜索，找到 CentOS 官方論壇的一篇帖子，帖子中有一回復(fù)如下：
Erase the existing version of openscap (I had openscap 1.2) and install openscap-1.0.8-1.0.1 from http://dev.centos.org/centos/6/upg and redo the upgrade.
根據(jù)他的方法，把 openscap 軟件包的版本降低之后，重新再安裝此工具及其預(yù)升級助手：
[root@allen05ren ~]# yum erase openscap
[root@allen05ren ~]# yum install https://buildlogs.centos.org/centos/6/upg/x86_64/Packages/openscap-1.0.8-1.0.1.el6.centos.x86_64.rpm
[root@allen05ren ~]# yum install redhat-upgrade-tool preupgrade-assistant-contents
