Is this a shared runner or your own private runner? If shared, take a look at this: What are Resource limits for CI jobs on GitLab.com? RAM? CPUs
Whilst this is an old post, it does mention the instance has 25GB. That said, only 16GB was available. Someone recently opened in issue here: Shared runners running out of disk space (#1146) · Issues · GitLab.com / GitLab Infrastructure Team / production · GitLab which also mentions problems with no space left failures.
As per the forum post, you may wish to disable shared runners and run your own private runner. That way you have more control over it, and can increase the disk space available by resizing the disk for the Gitlab Runner VM.
If you are already running your own runner, then chances are you need to resize the disk and make it bigger to allow your job to finish.