Artifact upload broken after upgrade to GL 12.4.0 chart 2.4.0

Summary

Starting Gitlab 12.4.0 (I think) Artifacts are accompanied by a metadata file which is uploaded seperately to a tempfs, which is not available at all nodes, which breaks all jobs which depend on the artifacts-feature being available.

Steps to reproduce

run jobs with artefacts on a chart with 2 or more unicorn instances with s3 configured for artifacts.

Configuration used

pretty much the default config

Current behavior

Artifact upload stage logs 3 response 500s, then fails the job

Expected behavior

artifacts get uploaded as expected

Versions

• Chart: (v2.4.0)
• Platform:
  • Kubernetes: 1.14.8
  • Client: 1.16.2
• Helm: (helm version)
  • Client: v2.11.0 < not the issue

Relevant logs

{"time":"2019-10-23T10:12:40.570Z","severity":"INFO","duration":66.45,"db":2.27,"view":64.18,"status":500,"method":"POST","path":"/api/v4/jobs/61804/artifacts","params":[{"key":"artifact_format","value":"zip"},{"key":"artifact_type","value":"archive"},{"key":"expire_in","value":"8h"},{"key":"file.remote_url","value":"https://<filtered>.s3-eu-central-1.amazonaws.com/tmp/uploads/1571825555-36-0017-7040-825c6a21b2102dbbc2f2a24b1f607380?X-Amz-Expires=15300&X-Amz-Date=20191023T101235Z&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=<filtered>2F20191023%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-SignedHeaders=host&X-Amz-Signature=<filtered>"},{"key":"file.size","value":"151957394"},{"key":"file.etag","value":"6ca74355fdc22ed31204e9f5925a4692-10"},{"key":"file.sha1","value":"2fe2aa73c43364ea8153681b9ef5ef3b4d039123"},{"key":"file.name","value":"artifacts.zip"},{"key":"file.remote_id","value":"1571825555-36-0017-7040-825c6a21b2102dbbc2f2a24b1f607380"},{"key":"file.sha256","value":"2ee82e8e68c9f3ca370e86c911063bdfde2e3c073bc23ecbcd42cc499b92e828"},{"key":"file.sha512","value":"a493d5102b961d6fb25f044305584fe95bb517e5ffacac94ae554a6234c22ce7a5737e4f2642f5549f83d6a89cc2303ac47ef836c0c8a7b48584a19ca1d9e720"},{"key":"file.md5","value":"2f10ed5bba9d264a7aa183d233de63a0"},{"key":"metadata.name","value":"metadata.gz"},{"key":"metadata.path","value":"/tmp/metadata.gz495512316"},{"key":"metadata.size","value":"207"},{"key":"metadata.md5","value":"97a722067ca58d4a576c732998fe8c10"},{"key":"metadata.sha1","value":"9db8f90b46523a790db878c27d0018ea79bed0b6"},{"key":"metadata.sha256","value":"58800145cd3774819c5d1105878539089f7ff7717c7a5214eb20511e1002e242"},{"key":"metadata.sha512","value":"401637a832bf14a3dce79397b47df90ab33d20b03c3f9190551efc3b1d88fbd8467fcf05bd5f9c0b6ea8c7c4292635b658703dda4dfc1e3071503524147935e7"}],"host":"gitlab.cofano.io","remote_ip":"3.121.237.241, 3.121.237.241","ua":"gitlab-runner 12.4.0 (12-4-stable; go1.10.8; linux/amd64)","route":"/api/:version/jobs/:id/artifacts","queue_duration":8.95,"correlation_id":"<filtered>"}

Errno::ENOENT (No such file or directory @ realpath_rec - /tmp/metadata.gz495512316):