My VM has an 8G ephemeral volume and it seems to be wasted so why not put the swapfile on there
You need the cloud-init service:
1 2 | sudo systemctl is-enabled cloud-init.serviceenabled |
The instructions with a couple of options are here: https://learn.microsoft.com/en-us/troubleshoot/azure/virtual-machines/linux/create-swap-file-linux-vm
Just in case the above link goes away:
Create a SWAP creation script named swap.sh under /var/lib/cloud/scripts/per-boot with the following script:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 | #!/bin/sh# Percent of space on the ephemeral disk to dedicate to swap. Here 30% is being used. Modify as appropriate.PCT=0.3# Location of the swap file. Modify as appropriate based on the location of the ephemeral disk.LOCATION=/mntif [ ! -f ${LOCATION}/swapfile ]then # Get size of the ephemeral disk and multiply it by the percent of space to allocate size=$(/bin/df -m --output=target,avail | /usr/bin/awk -v percent="$PCT" -v pattern=${LOCATION} '$0 ~ pattern {SIZE=int($2*percent);print SIZE}') echo "$size MB of space allocated to swap file" # Create an empty file first and set correct permissions /bin/dd if=/dev/zero of=${LOCATION}/swapfile bs=1M count=$size /bin/chmod 0600 ${LOCATION}/swapfile # Make the file available to use as swap /sbin/mkswap ${LOCATION}/swapfilefi# Enable swap/sbin/swapon ${LOCATION}/swapfile/sbin/swapon -a# Display current swap status/sbin/swapon -s |
The script will be executed on every boot and allocates 30% of the available space in the resource disk. You can customize the values based on your situation.
Make the script executable:
1 | chmod +x /var/lib/cloud/scripts/per-boot/swap.sh |
Stop and start the VM. Stopping and starting the VM is only necessary the first time after you create the SWAP file.
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