How to fix Singularity build has run out of space

You see an error message like this:

[alikhan@NBI-HPC bactdating]$ sudo singularity build  bactdating.sif bactdating.def
Using container recipe deffile: bactdating.def
Sanitizing environment
Adding base Singularity environment to container
Docker image path: index.docker.io/rocker/tidyverse:latest
Cache folder set to /root/.singularity/docker
[1/3] ||----------------------------------|   0.0% ERROR Error writing to /root/.singularity/docker/sha256:a1023bc917615cdb255c64fadbb2d8f78e8b0340fc6c11a8ea25e1020c475feb.tar.gz.LyNsUD.V1prNL: [Errno 28] No space left on device exiting
ERROR Error writing to /root/.singularity/docker/sha256:0c48f908dc6318e7ca082c5718e4fea9ef8c49809242b823587f452f73956b3e.tar.gz.D3S0er.Y8nPFj: [Errno 28] No space left on device exiting
ERROR Error writing to /root/.singularity/docker/sha256:a5729b5b4853988e207a18047cf059f520eea2a08a91d3bbcfc21554a5f98f0b.tar.gz.T88Q_a.UMjpkX: [Errno 28] No space left on device exiting

This tells you there is not enough space for Singularity to build your container.

What can you do?

You can disable the Singularity cache, or get it to write somewhere else. There are two variables to play with:

• SINGULARITY_DISABLE_CACHE If you want to disable the cache, this means is that the layers are written to a temporary directory. Thus, if you want to disable cache and write to a temporary folder, simply set SINGULARITY_DISABLE_CACHE to any true/yes value. By default, the cache is not disabled.
• SINGULARITY_CACHEDIR Is the base folder for caching layers and singularity hub images. If not defined, it uses default of $HOME/.singularity. If defined, the defined location is used instead.

Either of these could help avoid writing docker layers to /root/.singularity/docker.

Questions or comments? @ me on Twitter @happy_khan

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