RedHat – YUM Error: database disk image is malformed

As mentioned in one of my posts RedHat – Rebuild corrupted rpmdb today I have seen different error related to YUM/RPM. Clean the YUM dbcache. Rebuild the rpmdb.

RedHat – Useful YUM and RPM commands

Install the package YUM installs the package if it is not already present and updates it with the latest version available from repo if the package already installed and present. #yum install <package> Check which package (available from repo) provides the binary file/command. #yum provides <binary file/command> Often we want to see what are the … Continue reading RedHat – Useful YUM and RPM commands

AWS EC2 Linux Boot Problems – Root Volume

Below are the step by step instructions to recover EC2 instance if the system is not able to boot properly. So far I have seen couple of scenarios where it helped: -          Corrupted latest kernel ( initrd image is missing ) -          Not able to mount File system because of wrong entry in /etc/fstab and … Continue reading AWS EC2 Linux Boot Problems – Root Volume

Docker – Sharing data between containers

Procedure 1: Using Data Containers Step 1 - Create Container Data Containers are containers which sole responsibility to be a place to store/manage data. Like other containers they are managed by the host system. However, they don't run when you perform a docker ps command. To create a Data Container we first create a container with a … Continue reading Docker – Sharing data between containers

Docker – difference between CMD and ENTRYPOINT

The CMD line in a Dockerfile defines the default command to run when a container is launched. If the command requires arguments then you need to use an array, for example ["cmd", "-a", "arga value", "-b", "argb-value"], which will be combined together and the command cmd -a arga value -b argb-valuewould be run. An alternative approach to CMD is ENTRYPOINT. While … Continue reading Docker – difference between CMD and ENTRYPOINT