9.2 Setting Up Compute Nodes

First of all, we need compute nodes to mount those NFS directories that the head node exports. This can be done by adding the following lines to /etc/fstab:

head-node:/gnu/store    /gnu/store    nfs  defaults,_netdev,vers=3 0 0
head-node:/var/guix     /var/guix     nfs  defaults,_netdev,vers=3 0 0
head-node:/var/log/guix /var/log/guix nfs  defaults,_netdev,vers=3 0 0

... where head-node is the name or IP address of your head node. From there on, assuming the mount points exist, you should be able to mount each of these on the compute nodes.

Next, we need to provide a default guix command that users can run when they first connect to the cluster (eventually they will invoke guix pull, which will provide them with their “own” guix command). Similar to what the binary installation script did on the head node, we’ll store that in /usr/local/bin:

mkdir -p /usr/local/bin
ln -s /var/guix/profiles/per-user/root/current-guix/bin/guix \
      /usr/local/bin/guix

We then need to tell guix to talk to the daemon running on our master node, by adding these lines to /etc/profile:

GUIX_DAEMON_SOCKET="guix://head-node"
export GUIX_DAEMON_SOCKET

To avoid warnings and make sure guix uses the right locale, we need to tell it to use locale data provided by Guix (see Application Setup in GNU Guix Reference Manual):

GUIX_LOCPATH=/var/guix/profiles/per-user/root/guix-profile/lib/locale
export GUIX_LOCPATH

# Here we must use a valid locale name.  Try "ls $GUIX_LOCPATH/*"
# to see what names can be used.
LC_ALL=fr_FR.utf8
export LC_ALL

For convenience, guix package automatically generates ~/.guix-profile/etc/profile, which defines all the environment variables necessary to use the packages—PATH, C_INCLUDE_PATH, PYTHONPATH, etc. Likewise, guix pull does that under ~/.config/guix/current. Thus it’s a good idea to source both from /etc/profile:

for GUIX_PROFILE in "$HOME/.config/guix/current" "$HOME/.guix-profile"
do
  if [ -f "$GUIX_PROFILE/etc/profile" ]; then
    . "$GUIX_PROFILE/etc/profile"
  fi
done

Last but not least, Guix provides command-line completion notably for Bash and zsh. In /etc/bashrc, consider adding this line:

. /var/guix/profiles/per-user/root/current-guix/etc/bash_completion.d/guix

Voilà!

You can check that everything’s in place by logging in on a compute node and running:

guix install hello

The daemon on the head node should download pre-built binaries on your behalf and unpack them in /gnu/store, and guix install should create ~/.guix-profile containing the ~/.guix-profile/bin/hello command.