Merge pull request #61 from carpentriesoffline/jsteyn-patch-1

Create eessi_with_pxe.md

Author: jsteyn

eessi_with_pxe.md

@@ -0,0 +1,47 @@
+# Setting up EESSI with PXE
+
+To use eessi with PXE it is necessary to create a loop device for each compute node in the shared filesystem and then 
+mount it on /var/lib/cvmfs. 
+
+Creating a loop device:
+```bash
+sudo dd if=/dev/zero of=/sharedfs/loopdevices/${HOSTNAME} bs=4M count=5120
+sudo mkfs.ext4 /sharedfs/loopdevices/${HOSTNAME}
+```
+Create a script that can be run by systemd on bootup. In /usr/local/bin/cvfms-startup.sh enter:
+```
+#!/bin/bash
+
+/usr/sbin/losetup /dev/loop0 /sharedfs/loopdevices/${HOSTNAME}
+/bin/mount -o loop /dev/loop0 /var/lib/cvmfs
+cvmfs_config reload
+```
+
+Create the following systemd service script in /lib/systemd/system/cvmfs.service:
+```
+[Unit]
+Description=Setup Loop Device and Mount Shared Filesystem
+After=udev.service
+After=mountkernfs.service
+After=remote-fs.target
+
+[Service]
+Type=oneshot
+ExecStart=/usr/local/bin/cvmfs-setup.sh
+
+[Install]
+WantedBy=multi-user.target
+```
+
+Create a symbolic link in /etc/systemd/system to /lib/systemd/system/cvmfs.service:
+
+```
+cd /etc/systemd/system
+sudo ln -s /lib/systemd/system/cvmfs.service cvmfs.service
+```
+
+Enable and start the service:
+```
+sudo systemctl enable cvmfs.service
+sudo systemctl start cvmfs.service
+```