Upgrade CentOS 6.5 to CentOS 7

Upgrade CentOS 6.5 to CentOS 7

CentOS7 has been released, and I have been trying to test it on it. I have never had a chance. I can finally feel CentOS7 this time. CentOS6.5 has been used for some time, but since its kernel version remains at 2.6.32, it is decided to upgrade to CentOS7.

By the way, we upgraded the kernel to the latest 3.15.

After the upgrade, the disk suddenly has no space. When querying the log, we found that the messages file was written to 81 GB.

Then, delete the file and restart it. The following information is recorded in the log:

18:37:43, 729 ERR kernel: DMAR: [DMA Readdevice [0d: 00.0]

18:37:43, 730 ERR kernel: DMAR: [fault readevice [0d: 00.0] fault addr fffff000

After Google, the kernel needs to be disabled because CPU virtualization support is enabled.

Intel_iommu = off

But because I don't know if the 3.15 kernel has any other problems, I will switch back to 2.6.32.

If you talk so much about it, go to the topic here.

Refer to the online article: http://seven.centos.org/2014/07/testing-centos-6-to-centos-7-upgrades-via-centos-testing-repo/

Main steps:

1. Add a repo file:

/Etc/yum. repos. d/upgradetool. repo

Name = CentOS-$ releasever-Upgrade Tool
Base url = http://dev.centos.org/centos/6/upg/x86_64/
Gpgcheck = 1
Enabled = 1
Gpgkey = file: // etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6

2. Install the upgrade Toolkit

Yum install RedHat-upgrade-tool preupgrade-assistant-contents

3. view available update Directories

Preupg-l

If the result is CentOS6_7, continue:

Preupg-s CentOS6_7

At this time, it will analyze the potential risks of upgrading the system. The danger here is classified. For details, refer to my reference article.

4. upgrade the system

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

Here, if the prompt is displayed: the upgrade is dangerous and cannot be upgraded, force the upgrade directly:

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

During the upgrade, the gpg key of the CentOS7 software warehouse is interrupted. Execute:

Rpm -- import http://mirror.centos.org/centos/7/ OS /x86_64/RPM-GPG-KEY-CentOS-7

Then run the system upgrade command.

After the upgrade package is downloaded, restart the package and configure the new software package. In this case, you only need to have a cup of coffee.

After the upgrade, the graphic interface cannot be accessed. You can only enter the character interface. I do not know if it is caused by gnome Desktop upgrade to 3.0.

Upgrading from CentOS 6 to CentOS 7

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Precautions for installing CentOS and Windows systems

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