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cloud engineer

yum

Yum Cache Corruption

If you’re getting a “HTTP Error 404 – Not Found” error when trying to run yum update, it could be a corrupted cache. Clear the cache on the system by running the following.

yum clean all
rm -rf /var/cache/yum/*

Run yum update again. The errors should be gone.

Lock a Package in Linux

Here’s how to lockdown a package to a specific version.

Search for the current package.

$ sudo rpm -qa |  grep sdk
google-cloud-sdk-365.0.1-1.x86_64

Install versionlock.

yum install yum-plugin-versionlock

Lock a package.

yum versionlock google-cloud-sdk-365.0.1-1.x86_64

Display all locked versions.

yum versionlock list

Unlock and clear.

yum versionlock clear

Create Local Yum Repo

Here’s how to create a local yum repo.

Install Apache.

sudo yum install httpd
sudo systemctl start httpd
sudo systemctl enable httpd
sudo systemctl status httpd

Install the repo packages.

sudo yum install createrepo yum-utils

Create repo directories.

sudo mkdir /var/www/html/{baseos,extras,appstream,epel}

Sync the repos.

sudo yum reposync -p=/var/www/html --repoid=baseos --download-metadata
sudo yum reposync -p=/var/www/html --repoid=extras --download-metadata
sudo yum reposync -p=/var/www/html --repoid=appstream --download-metadata
sudo yum reposync -p=/var/www/html --repoid=epel --download-metadata

Create a new repo.

sudo createrepo /var/www/html/

Setup a local repo.

sudo nano /etc/yum.repos.d/local.repo

Contents of local.repo.

local-base]
name=Yum Local Base
baseurl=http://10.10.0.20:80/base
enabled=1
gpgcheck=0
[local-extras]
name=Yum Local Extras
baseurl=http://10.10.0.20:80/extras
enabled=1
gpgcheck=0
[local-appstream]
name=Yum Local Appstream
baseurl=http://10.10.0.20:80/appstream
enabled=1
gpgcheck=0
[local-epel]
name=Yum Local Epel
baseurl=http://10.10.0.20:80/epel
enabled=1
gpgcheck=0

Confirm new repo is in the repolist.

sudo yum repolist

Database Clients on Linux

You can run database clients on your Linux distro by installing them.

MySQL

$ yum install mysql
$ apt install mysql

Postgress

$ yum install postgresql postgresql-client
$ apt install postgresql postgresql-client

MSSQL

$ yum install mysql-tools
$ apt install mssql-tools

rpmdb open failed

If you get this error, something happened to the rpm database. To fix.

rm -f /var/lib/rpm/__db*
db_verify /var/lib/rpm/Packages
rpm --rebuilddb
yum clean all

Run yum again.

Checking Yum Transaction Logs

Check if package is on the system.

rpm -q httpd
httpd-2.4.6-97.el7.centos.x86_64

Check the history logs.

yum history list
Loaded plugins: fastestmirror
ID     | Login user               | Date and time    | Action(s)      | Altered
-------------------------------------------------------------------------------
   115 | System <unset>           | 2021-02-01 03:40 | Update         |    1
   114 | System <unset>           | 2021-02-01 02:03 | I, U           |   10
   113 | System <unset>           | 2021-01-29 19:54 | Update         |    1
   112 | System <unset>           | 2021-01-21 14:41 | Update         |    1

Check detail transaction id.

yum history info 114 | grep python 
    Updated python-perf-3.10.0-1160.6.1.el7.x86_64          @updates
    Updated python-sss-1.16.5-10.el7_9.5.x86_64             @your-repo
    Updated python-sssdconfig-1.16.5-10.el7_9.5.noarch      @your-repo

It looks like python was updated in transaction id #114.

Yum localinstall

Here’s how to install a RPM locally. Download the RPM first.

wget https://domain.com/path/to/file/rpmfile1.rpm
wget https://domain.com/path/to/file/rpmfile2.rpm

Then install RPM from a local file.

yum localinstall /path/to/rpmfile1.rpm
yum localinstall /path/to/rpmfile2.rpm