cloud engineer
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/* |
yum clean all rm -rf /var/cache/yum/*
Run yum update again. The errors should be gone.
If you tried to run apt update and you get this error, try the following.
$ apt update E: Could not get lock /var/lib/dpkg/lock-frontend - open (11: Resource temporarily unavailable) [duplicate] |
$ apt update E: Could not get lock /var/lib/dpkg/lock-frontend - open (11: Resource temporarily unavailable) [duplicate]
Kill the process.
$ sudo killall apt apt-get |
$ sudo killall apt apt-get
If that doesn’t work, remove the locked files.
$ sudo rm /var/lib/apt/lists/lock $ sudo rm /var/cache/apt/archives/lock $ sudo rm /var/lib/dpkg/lock* |
$ sudo rm /var/lib/apt/lists/lock $ sudo rm /var/cache/apt/archives/lock $ sudo rm /var/lib/dpkg/lock*
Run apt update again.
If you get a WordPress “There has been a critical error on your website” error, you probably have an issue with a theme or plugin. The quickest way to troubleshoot is to rename the plugins directory since there’s no way to login. This technically disables all plugins. Rename it back to plugins and enable each plugin one by one.
Disable all plugins.
mv plugins plugins-backup |
mv plugins plugins-backup
Login and restore the plugins directory.
mv plugins-backup plugins |
mv plugins-backup plugins
Enable each plugin one by one and check if the site is broken.
If you are getting an error similar to the yum error below, yum may be broken in your system.
error: rpmdb: BDB0113 Thread/process 2196/139984719730496 failed: BDB1507 Thread died in Berkeley DB library error: db5 error(-30973) from dbenv->failchk: BDB0087 DB_RUNRECOVERY: Fatal error, run database recovery error: cannot open Packages index using db5 - (-30973) error: cannot open Packages database in /var/lib/rpm CRITICAL:yum.main: Error: rpmdb open failed |
error: rpmdb: BDB0113 Thread/process 2196/139984719730496 failed: BDB1507 Thread died in Berkeley DB library error: db5 error(-30973) from dbenv->failchk: BDB0087 DB_RUNRECOVERY: Fatal error, run database recovery error: cannot open Packages index using db5 - (-30973) error: cannot open Packages database in /var/lib/rpm CRITICAL:yum.main: Error: rpmdb open failed
Here’s the fix.
mv /var/lib/rpm/__db* /tmp yum clean all |
mv /var/lib/rpm/__db* /tmp yum clean all
Run your yum commands. The errors should be gone.
How to recover a MySQL root password without a password.
# Stop MySQL. service mysql stop # MySQL Safe Mode. mysqld_safe --skip-grant-tables & |
# Stop MySQL. service mysql stop # MySQL Safe Mode. mysqld_safe --skip-grant-tables &
# Login to MySQL without password. Set new password. mysql -u root -p use mysql; # For MySQL 5.6 or lower UPDATE mysql.user SET Password=PASSWORD('newpassword') WHERE User='root'; # For MySQL 5.7 or higher SET PASSWORD FOR 'root'@'localhost' = PASSWORD("newpassword"); FLUSH PRIVILEGES; exit; |
# Login to MySQL without password. Set new password. mysql -u root -p use mysql; # For MySQL 5.6 or lower UPDATE mysql.user SET Password=PASSWORD('newpassword') WHERE User='root'; # For MySQL 5.7 or higher SET PASSWORD FOR 'root'@'localhost' = PASSWORD("newpassword"); FLUSH PRIVILEGES; exit;
# Kill mysqld killall mysqld # Restart MySQL service mysql start |
# Kill mysqld killall mysqld # Restart MySQL service mysql start
I ran into issues running MySQL Safe mode. I got a “UNIX socket file don’t exists” error. Here’s the fix.
mkdir -p /var/run/mysqld chown mysql:mysql /var/run/mysqld |
mkdir -p /var/run/mysqld chown mysql:mysql /var/run/mysqld