Kubernetes Pods Terminated - Exit Code 137

I need some advise on an issue I am facing with k8s 1.14 and running gitlab pipelines on it. Many jobs are throwing up exit code 137 errors and I found that it means that the container is being terminated abruptly.

Cluster information:

Kubernetes version: 1.14 Cloud being used: AWS EKS Node: C5.4xLarge

After digging in, I found the below logs:

**kubelet: I0114 03:37:08.639450**  4721 image_gc_manager.go:300] [imageGCManager]: Disk usage on image filesystem is at 95% which is over the high threshold (85%). Trying to free 3022784921 bytes down to the low threshold (80%).

**kubelet: E0114 03:37:08.653132**  4721 kubelet.go:1282] Image garbage collection failed once. Stats initialization may not have completed yet: failed to garbage collect required amount of images. Wanted to free 3022784921 bytes, but freed 0 bytes

**kubelet: W0114 03:37:23.240990**  4721 eviction_manager.go:397] eviction manager: timed out waiting for pods runner-u4zrz1by-project-12123209-concurrent-4zz892_gitlab-managed-apps(d9331870-367e-11ea-b638-0673fa95f662) to be cleaned up

**kubelet: W0114 00:15:51.106881**   4781 eviction_manager.go:333] eviction manager: attempting to reclaim ephemeral-storage

**kubelet: I0114 00:15:51.106907**   4781 container_gc.go:85] attempting to delete unused containers

**kubelet: I0114 00:15:51.116286**   4781 image_gc_manager.go:317] attempting to delete unused images

**kubelet: I0114 00:15:51.130499**   4781 eviction_manager.go:344] eviction manager: must evict pod(s) to reclaim ephemeral-storage 

**kubelet: I0114 00:15:51.130648**   4781 eviction_manager.go:362] eviction manager: pods ranked for eviction:

 1. runner-u4zrz1by-project-10310692-concurrent-1mqrmt_gitlab-managed-apps(d16238f0-3661-11ea-b638-0673fa95f662)
 2. runner-u4zrz1by-project-10310692-concurrent-0hnnlm_gitlab-managed-apps(d1017c51-3661-11ea-b638-0673fa95f662)

 3. runner-u4zrz1by-project-13074486-concurrent-0dlcxb_gitlab-managed-apps(63d78af9-3662-11ea-b638-0673fa95f662)

 4. prometheus-deployment-66885d86f-6j9vt_prometheus(da2788bb-3651-11ea-b638-0673fa95f662)

 5. nginx-ingress-controller-7dcc95dfbf-ld67q_ingress-nginx(6bf8d8e0-35ca-11ea-b638-0673fa95f662)

And then the pods get terminated resulting in the exit code 137s.

Can anyone help me understand the reason and a possible solution to overcome this?

Thank you :)