Migration help: Gitlab 12.7.6 from EC2 to EKS - Helm chart compatibility & backup restore issues

How to Use GitLab Migrations
1

IssueSummary end

I’m trying to migrate a Gitlab CE 12.7.6 instance from an EC2 ( Amazon linux 2018) environment to EKS but i’m running into multiple road blocks due to version compatibility and helm chart limitations

Current Environment

  • GitLab CE: 12.7.6

  • Host: EC2 instance

  • OS: Amazon Linux 2 (2018)

  • Database: External RDS PostgreSQL 15.13

  • Storage: Local EC2 disk for repositories and config

Migration Goal

  • Move GitLab CE 12.7.6 from EC2 → EKS (Kubernetes)

  • Deploy using GitLab Helm chart

  • Continue using RDS (Postgres 15.13)

  • Store repos on EBS-backed PVCs in EKS

What I Have So Far

  1. Backups (taken manually on EC2):

    • gitlab_config_backup.tar.gz

    • gitlab_db_backup.sql

    • gitlab_repos_backup.tar.gz
      (Couldn’t use gitlab-backup create because omnibus GitLab 12.7.6 was failing.)

  2. Helm chart attempt:

    • Tried chart 3.0.4 (closest to GitLab 12.x).

    • Ran into template errors (haskey misuse).

    • Current Helm charts (6.x+) only support GitLab 13+.

  3. Database restore attempt:

    • Loaded gitlab_db_backup.sql into RDS (Postgres 15.13).

    • GitLab pods failed with schema mismatch error:

  4. Pods status:

    • Sidekiq & Webservice stuck in CrashLoopBackOff

    • Toolbox pod runs (used for restore).

Challenges

  • No unified gitlab_backup.tar (Helm restore expects this).

  • Restoring GitLab 12.x DB dump into Postgres 15.13 causes schema mismatch.

  • Unsure how to reconcile repos/config restores into Helm deployment.

  • Helm chart for 12.x is broken/unmaintained.

  • In-place EC2 upgrade risky (old Amazon Linux).

  1. What’s the safest upgrade/migration path from GitLab CE 12.7.6 → EKS with Postgres 15.13?

  2. Should we:

    • Upgrade GitLab on EC2 until we can generate a valid backup tar (then move to EKS), or

    • Stand up an intermediate GitLab 13.x/14.x (VM or EKS), restore backups there, then upgrade to 15.x?

  3. Has anyone successfully restored separate DB + repos + config backups into a Helm-based GitLab?

  4. Which Helm chart (if any) can work reliably with GitLab 12.7.6?