Elastic Compute Service:Add or repair an Alibaba Cloud software repository for a Linux instance

Problem description

When you run a yum command to install MySQL on an ECS instance that runs CentOS 7.0, the following error message appears:

File contains no section headers.

Cause

The software repository does not provide the relevant software package.

Solution

To switch to the official CentOS software repository, perform the following steps:

1. Connect to the Linux ECS instance.

   For more information, see Use Workbench to connect to a Linux instance over SSH.

2. Modify the /etc/yum.repos.d/epel.repo configuration file.

   1. Run the following command to open the /etc/yum.repos.d/epel.repo configuration file:

      vim /etc/yum.repos.d/epel.repo

   2. Press the I key to enter Insert mode and replace the content of the configuration file with the following content:

      [epel-source]
      name=Extra Packages for Enterprise Linux 7 - $basearch - Source
      #baseurl=http://download.fedoraproject.org/pub/epel/7/SRPMS
      mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-source-7&arch=$basearch
      failovermethod=priority
      enabled=0
      gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-7
      gpgcheck=1
      
      [epel] 
      name=Extra Packages for Enterprise Linux 7 - $basearch #baseurl=http://download.fedoraproject.org/pub/epel/7/$basearch mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-7&arch=$basearch 
      failovermethod=priority 
      enabled=1 
      gpgcheck=0 
      gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-7 
      
      [epel-debuginfo]
      name=Extra Packages for Enterprise Linux 7 - $basearch - Debug #baseurl=http://download.fedoraproject.org/pub/epel/7/$basearch/debug mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-debug-7&arch=$basearch failovermethod=priority 
      enabled=0 
      gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-7 
      gpgcheck=1

   3. Press the Esc key to exit Insert mode. Then, enter :wq and press the Enter key to save and close the file.

3. Run the following commands in sequence to make the new software repository take effect:

   yum makecache
   yum repolist

4. Re-install MySQL. If the issue is resolved, the preceding error message no longer appears.

Problem description

When you run the apt-get command to install software on an ECS instance that runs Ubuntu, the error processing package install-info (--configure) error message appears.

Cause

The preceding issue may occur because the Ubuntu software package is corrupted, which results in a software installation failure.

Solution

To update and synchronize the APT software repository and re-install the software, perform the following steps:

1. Connect to the Ubuntu instance.

   For more information, see Use Workbench to connect to a Linux instance over SSH.

2. Rename the info folder.

   mv /var/lib/dpkg/info/ /var/lib/dpkg/info.bak.old/

3. Create a new info folder.

   mkdir /var/lib/dpkg/info/

4. Run the following command to update and synchronize the APT software repository:

   apt-get update

5. Run the following command to re-install the software. Replace <xxxxx> with the name of the software package that you want to re-install. If the issue is resolved, the preceding error message no longer appears.

   apt-get install <xxxxx>

Problem description

When you run the apt-get command to install or update software on an ECS instance that runs Ubuntu, the Segmentation faultsts" error occurs.

Cause

The preceding issue may occur because of a conflict in the APT cache, which results in a software installation or update failure.

Solution

Perform the following steps to update and synchronize the APT software repository:

1. Connect to the Ubuntu instance.

   For more information, see Use Workbench to connect to a Linux instance over SSH.

2. Back up files in the /var/cache/apt/ directory.

3. Run the following command to delete all .bin files from the /var/cache/apt/ directory:

   rm /var/cache/apt/*.bin

4. Run the following command to update and synchronize the APT software repository:

   apt-get update

5. Check whether you can run the apt-get command to install or update software as expected.

   Note

   If the Segmentation faults error occurs on an ECS instance that has a low memory specification, such as a memory size of only 512 MB, you can also run the top command to check the memory usage, temporarily stop specific non-essential processes, and then rerun the apt-get command.

Problem description

When you run the apt-get command to install software on an ECS instance that runs Ubuntu, the following error message appears:

Reading package lists... Error!  E: Encountered a section with no Package: header E: Problem with MergeList /var/lib/apt/lists/AZ.archive.ubuntu.com_ubuntu_dists_natty_main_i18n _Translation-en E: The package lists or status file could not be parsed or opened.

Cause

The software package list is corrupted, which causes a software installation error.

Solution

To clear the corrupted software package list and regenerate the latest software package list, perform the following steps:

1. Run the following command to clear the corrupted software package list from the software package list directory:

   rm -rf /var/lib/apt/lists/*

2. Run the following command to regenerate the latest software package list:

   apt-get update

   

3. Re-install the software. If the issue is resolved, the preceding error message no longer appears.

Problem description

When you run the apt-get install unzip or aptitude install unzip command on an ECS instance that runs Ubuntu, the following error message appears:

Error http://mirrors.aliyun.com/ubuntu/ trusty-updates/main unzip amd64 6.0-9ubuntu1.1 404 Not Found [IP: 112.124.XXX.XXX 80]
Error http://mirrors.aliyun.com/ubuntu/ trusty-updates/main unzip amd64 6.0-9ubuntu1.1 404 Not Found [IP: 112.124.XXX.XXX 80]
Error http://mirrors.aliyun.com/ubuntu/ trusty-updates/main unzip amd64 6.0-9ubuntu1.1 404 Not Found [IP: 112.124.XXX.XXX 80]

Cause

In most cases, the preceding issue occurs because the software version requested by the command does not exist in the APT software repository.

Solution

To update and synchronize the APT software repository, perform the following steps:

1. Connect to the Ubuntu instance.

   For more information, see Use Workbench to connect to a Linux instance over SSH.

2. Run the following command to update and synchronize the APT software repository:

   apt-get update

3. After the APT software repository is updated and synchronized, run the apt-get install command to install the required software.

Problem description

When you run the apt-get update command on an Ubuntu instance, the following error message appears:

The following signatures were invalid: KEYEXPIRED 1544811256

Cause

An update error occurred because the signatures of the used software repository expired.

Solution

Perform the following steps to update the expired key:

1. Connect to the Ubuntu instance.

   For more information, see Use Workbench to connect to a Linux instance over SSH.

2. Run the following command to obtain the expired key:

   sudo apt-key list | grep -A 1 expired

   

3. Run the following command to update the expired key:

   apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys [$Key]

   Note

   Replace [$Key] with the expired key that you obtained in the previous step.

4. Run the following command to update and synchronize the APT software repository:

   apt-get update

Problem description

When you use third-party YUM repositories, such as Docker Community Edition (Docker-CE) and Extra Packages for Enterprise Linux (EPEL) repositories, that are compatible with CentOS 7 and run the yum install docker-ce command to install Docker on an Alibaba Cloud Linux 2 instance that meets the following conditions, Docker cannot be installed and the following error message is returned.

• The instance uses the Alibaba Cloud Linux 2.1903 LTS 64-bit image.

• The image used by the instance is aliyun_2_1903_x64_20G_alibase_20210325.vhd or earlier.

Loaded plugins: fastestmirror, langpacks, update-motd
Loading mirror speeds from cached hostfile
  * epel: mirror.sjtu.edu.cn 
https://mirrors.aliyun.com/docker-ce/linux/centos/2.1903/x86_64/stable/repodata/repomd.xml: [Errno 14] HTTPS Error 404 - Not Found 
Trying other mirror.
Downloading packages:
docker-ce-20.10.6-3.el7.x86_64 FAILED
https://mirrors.aliyun.com/docker-ce/linux/centos/2.1903/x86_64/stable/Packages/docker-ce-20.10.6-3.el7.x86_64.rpm: [Errno 14] HTTPS Error 404 - Not Found 
Trying other mirror.
docker-ce-rootless-extras-20.1 FAILED
https://mirrors.aliyun.com/docker-ce/linux/centos/2.1903/x86_64/stable/Packages/docker-ce-rootless-extras-20.10.6-3.el7.x86_64.rpm: [Errno 14] HTTPS Error 404 - Not Found
 Trying other mirror. 


Error downloading packages:
  3:docker-ce-20.10.6-3.el7.x86_64: [Errno 256] No more mirrors to try.
  docker-ce-rootless-extras-20.10.6-3.el7.x86_64: [Errno 256] No more mirrors to try.

Cause

Third-party YUM repositories are compatible only with CentOS 7. The $releasever value of Alibaba Cloud Linux 2 is different from that of CentOS 7. As a result, the Docker package cannot be downloaded because the resolved YUM repository addresses are invalid.

Solutions

Use one of the following methods to resolve the issue:

• Perform the operations described in Solution 1: Change the $releasever value to change the value of $releasever.

• Perform the operations described in Solution 2: Use a plug-in to change the $releasever value to install the yum-plugin-releasever-adapter plug-in, and then use the plug-in to change the value of $releasever.

Problem description

You cannot install Docker by running the dnf install docker-ce command on an Alibaba Cloud Linux 3 instance that meets the following conditions, and an error message is returned.

• The instance uses third-party DNF repositories that are compatible with CentOS 8.

• The instance uses an image of the aliyun_3_x64_20G_alibase_20210425.vhd version or earlier.

Sample error message:

Docker CE Stable - x86_64
Failed to download metadata for repo 'docker-ce-stable'
Error: Failed to download metadata for repo 'docker-ce-stable'

Cause

Third-party DNF repositories are compatible only with CentOS 8. The $releasever value of Alibaba Cloud Linux 3 is different from that of CentOS 8. As a result, the Docker package cannot be downloaded because the resolved DNF repository addresses are invalid.

Solutions

Use one of the following methods to resolve the issue:

• Perform the operations described in Solution 1: Change the $releasever value to change the value of $releasever.

• Perform the operations described in Solution 2: Use a plug-in to change the $releasever value to install the dnf-plugin-releasever-adapter plug-in, and then use the plug-in to change the value of $releasever.

Problem description

When you run a yum command on an ECS instance that runs CentOS 7, the following error message appears:

-bash: /usr/bin/yum: /usr/bin/python: bad interpreter: No such file or directory

Cause

The preceding issue may be caused by a Python exception, such as when Python is uninstalled, a file is renamed, or a file path is moved.

Solution

To check whether a Python exception occurs and repair the exception, perform the following steps:

1. Connect to the Linux ECS instance.

   For more information, see Use Workbench to connect to a Linux instance over SSH.

2. Run the following command to query the YUM file path:

   which yum

   The following command output indicates that the YUM file path is /usr/bin/yum.

   /usr/bin/yum

3. Run the following command to view the YUM content:

   cat /usr/bin/yum

   The following command output indicates that the path of the Python version is used.

   #!/usr/bin/python

   Note

   In the following example, the /usr/bin/python path is used. Replace the path with the actual path.

4. Run the following command to check the preceding path:

   ls -al /usr/bin/python

   If the following command output is displayed, Python may be uninstalled, the names of Python-related files may be changed, or the paths of Python-related files may be moved.

   ls: cannot access /usr/bin/python: No such file or directory

5. Run the following command to check whether Python-related files exist:

   rpm -qa | grep python

   If Python-related files exist, the following command output is displayed:

   python-decorator-3.4.0-3.el7.noarch
   libselinux-python-2.5-14.1.el7.x86_64
   python-backports-1.0-8.el7.x86_64
   python-pyudev-0.15-9.el7.noarch
   rpm-python-4.11.3-35.el7.x86_64
   python-2.7.5-76.el7.x86_64
   .....

   • If Python-related files exist, this indicates that the names of the files were changed or the paths of the files were moved.

     1. Run the following command to view Python-related files:

        ls -al /usr/bin/python*

        The following command output is displayed, in which /usr/bin/python.bak -> python2 indicates that the name of Python was changed.

        lrwxrwxrwx  1 root root   14 Feb 15  2019 /usr/bin/python-config -> python2-config
        lrwxrwxrwx. 1 root root    7 Feb 15  2019 /usr/bin/python.bak -> python2
        lrwxrwxrwx. 1 root root    9 Feb 15  2019 /usr/bin/python2 -> python2.7
        lrwxrwxrwx  1 root root   16 Feb 15  2019 /usr/bin/python2-config -> python2.7-config
        -rwxr-xr-x. 1 root root 7216 Oct 31  2018 /usr/bin/python2.7
        -rwxr-xr-x  1 root root 1835 Oct 31  2018 /usr/bin/python2.7-config

     2. Run the following command to change /usr/bin/python.bak to /usr/bin/python:

        mv python.bak python

     3. Rerun the yum command. If the issue is resolved, the preceding error message no longer appears.

   • If Python-related files do not exist, this indicates that Python was uninstalled.

     1. Run the following commands in sequence to install Python:

        mkdir /python/
          
        yum install python --downloadonly --downloaddir=/python/

     2. Rerun the yum command. If the issue is resolved, the preceding error message no longer appears.