Frequently Asked Questions

Questions and their answers.

This section is under construction.

what xdc am i on? (lighthouse)

export XDC=$(uname -a | cut -d' ' -f2 | cut -d'-' -f1)
echo ${XDC}

what materialization is my xdc connected to? (lighthouse)

export MERGE_MATERIALIZATION=$(head -1 /etc/resolv.conf | cut -d' ' -f2 | grep -Ev "cluster.local|")

Result will be empty if your XDC is not connected to a materialization.

Ansible error: “Message: Cannot write to ControlPath $HOME/.ansible/cp.”

Check to make sure the .ansible directory exists in your home directory, and that its owner and group is you (not root):

# check if the directory exists and its ownership
$ ls -ald ~/.ansible

# create the directory if it does not exist
$ mkdir ~/.ansible

# change the user and group ownership of directory to yourself
$ sudo chown -R $(id -u):$(id -g) ~/.ansible

EFI variable error on apt dist-upgrade (mod deter, ubuntu)

When upgrading a node via apt, you see an error like the following:

grub-install: warning: Cannot set EFI variable Boot0009.
grub-install: warning: efivarfs_set_variable: failed to open /sys/firmware/efi/efivars/Boot0009-8be4df61-93ca-11d2-aa0d-00e098032b8c for writing: Read-only file system.
grub-install: warning: _efi_set_variable_mode: ops->set_variable() failed: Read-only file system.
grub-install: error: failed to register the EFI boot entry: Read-only file system.

Merge nodes do not permit modifying EFI variables. The Merge infrastructure needs to preserve these so that we can provide a reliable boot procedure. We workaround this limitation through the following in our playbooks:

# hold back kernel/grub updates
- name: Holdback kernel and grub-efi packages
    name: "{{ item }}"
    selection: hold
    - linux-generic
    - grub-efi
    - grub-efi-amd64

this is akin to apt-mark hold on debian/ubuntu systems. After which apt upgrade will no longer try to upgrade packages that try to modify EFI variables After adding this, re-run your ansible commands.

Last modified March 17, 2023: fixed error in FAQ title (f1544a0)