Nix pkg unable to install or delete packages

OS: Arch Linux Tags:#linux#nix#packages

Description: Error: this derivation has bad ‘meta.outputsToInstall/Uninstall’ References:

Reproduce: After trying to install or uninstall a package: nix-env -e calibre or trying to upgrade a package: nix-env -u --always calibre

would see this error Error: this derivation has bad 'meta.outputsToInstall/Uninstall

Solution: save list of packages with nix-env -q > cur.gen switch to pretty old generation like 1 month ago nix-env --list-generations and nix-env --switch-generation 50 run nix-channel --update and nix-env -u uninstall the packages that no longer needed and install the packages that saved at start.

Unable to Update CentOS7

OS: CentOS 7 or 8 Tags:#linux#CentOS#Update#YUM Description: Cant Update system References:

yum update -y
Error: Failed to download metadata for repo 'appstream': Cannot prepare internal mirrorlist: No URLs in mirrorlist

Solution: Go to /etc/yum.repos.d/


sudo sed -i 's/mirrorlist/#mirrorlist/g' /etc/yum.repos.d/CentOS-*`
sudo sed -i 's|#baseurl=|baseurl=|g' /etc/yum.repos.d/CentOS-*
`sudo yum update -y

Communicate different pods using Podman

OS: Arch Linux Tags:#podman#Docker#network References:

Description: I am deploying several Pods using podman-compose. To do so, each pod has its own definition in a podman-compose.yaml file that I execute in rootless mode (so all containers in a Pod coexist in the same host/IP). However, I would like to make able a container in a Pod to reach a service exposed by a container in another pod.


podman network create $NETWORK_NAME

podman pod create --name $POD1 --network $NETWORK_NAME

podman pod create --name $POD2 --network $NETWORK_NAME

podman run -it --detach --pod $POD1 --name $CONTAINER1 --network $NETWORK_NAME image_name

podman run -it --detach --pod $POD2 --name $CONTAINER2 --network $NETWORK_NAME image_name

Unable to Connect to EC2 instance with RDP

Type: Fixed RDP EC2 Instance cert error OS: Amazon Linux (Fedora base) Tags:#AWS,#cloud,#EC2,#RDP

Description: While trying to run GUI EC2 instance (MATE Desktop Enviroment) I got this certificate error while checking log with systemctl status xrdp .... /etc/xrdp/cert.pem and key.pem not found Something like this

Solution: so we should generate the keys for them. just login with ssh or ec2-connect from gui and run this command sudo openssl req -x509 -newkey rsa:2048 -nodes -keyout /etc/xrdp/key.pem -out /etc/xrdp/cert.pem -days 365

and reload the RDP service systemctl restart xrdp

Extra Notes: -