Summary

This article provides solutions for resolving issues related to pipelines running on self-hosted runners, specifically addressing the error message:

Your kernel does not support memory swappiness capabilities or the cgroup is not mounted. Memory swappiness discarded.

Environment

Linux Docker (x86_64) Runner.

Cause

This issue is OS-specific or the issue with the grub configuration and not related to Bitbucket. To avoid this warning, follow the steps below to check and configure your system.

Solution

• Verify if Swappiness is Enabled on Your Host:
  
  

  • To verify if swappiness is enabled, use the following command:

    sysctl vm.swappiness

    This command will output the current value of swappiness. If the value is non-zero, it means swappiness is enabled.
    
    

  • If sysctl is not available, you can directly check the value in the /proc/sys/vm/swappiness file:

    cat /proc/sys/vm/swappiness

    The default value for vm.swappiness is typically 60.
    
    

• Enable Swappiness if Necessary:
   

  • If swappiness is not enabled, you can enable it by running the following command:

    sudo sysctl vm.swappiness=60

    
    

If the issue persists after enabling swappiness, it might be related to the OS and its GRUB configuration. For example, if your self-hosted runner is hosted on Ubuntu 22.04, you need to modify the GRUB configuration as follows:

• Modify GRUB Configuration:
   

  • Edit the GRUB configuration file, typically located at /etc/default/grub:

    vi /etc/default/grub

  • Add or append the following lines in the file:

    GRUB_CMDLINE_LINUX_DEFAULT="cgroup_enable=memory swapaccount=1"
    GRUB_CMDLINE_LINUX="cgroup_enable=memory cgroup_memory=1 systemd.unified_cgroup_hierarchy=0"

    For additional information, you can refer to the discussion on enabling memory cgroups in Ubuntu: Enabling Memory Cgroup in Ubuntu 20.04