Scheduler and worker will not start as they are waiting for migrations when using external PostgreSQL

[james-ro-williams]

Checks

• I have checked for existing issues.
• This report is about the User-Community Airflow Helm Chart.

Chart Version

1.15.0

Kubernetes Version

Client Version: v1.30.2
Server Version: v1.30.6-eks-7f9249a

### Helm Version

```shell
version.BuildInfo{Version:"v3.16.2", GitCommit:"13654a52f7c70a143b1dd51416d633e1071faffb", GitTreeState:"clean", GoVersion:"go1.22.7"}

### Description

I was attempting to start Airflow using Helm and using an external AWS RDS PostgreSQL instance as the database. Pods such as the worker and triggerer hang with the logs: 

Created container wait-for-airflow-migrations
Started container wait-for-airflow-migrations

I have proved that the RDS instance is reachable from within the cluster, and I have manually created the database user and tables in an effort to solve this issue.

### Relevant Logs

```shell
Output of `kubectl get pods -n airflow`:

airflow-redis-0                        1/1     Running                 0               12m
airflow-run-airflow-migrations-7c4qd   1/1     Running                 4 (112s ago)    12m
airflow-scheduler-d667c946d-mljlx      1/2     Running                 7 (3m45s ago)   12m
airflow-statsd-b45f54fb4-f5vgg         1/1     Running                 0               12m
airflow-triggerer-0                    0/2     Init:CrashLoopBackOff   3 (15s ago)     12m
airflow-webserver-75d89cb74d-68bz7     0/1     CrashLoopBackOff        7 (13s ago)     12m
airflow-worker-0                       0/2     Init:CrashLoopBackOff   3 (14s ago)     12m

Output of kubectl describe pod airflow-triggerer-0 -n airflow:

Normal   Pulled                  6s (x5 over 12m)     kubelet                  Container image "apache/airflow:2.9.3" already present on machine
  Normal   Created                 6s (x5 over 12m)     kubelet                  Created container wait-for-airflow-migrations
  Normal   Started                 6s (x5 over 12m)     kubelet                  Started container wait-for-airflow-migrations

Custom Helm Values

postgresql:
  ## to use the external db, the embedded one must be disabled
  enabled: false

  ## for full list of PgBouncer configs, see values.yaml
  pgbouncer:
    enabled: true

  externalDatabase:
    type: postgres
    host: <hostname>
    port: 5432

    ## the database/scheme to use within the external database
    database: airflow_db
  
    ## (username - option 1) a plain-text helm value
    user: airflow_user 
    password: <password here>

triggerer:
  persistence:
    storageClassName: dev-ebs-sc-hot-storage 
workers:
  persistence:
    storageClassName: dev-ebs-sc-hot-storage 
redis:
  persistence:
    storageClassName: dev-ebs-sc-hot-storage 
dags:
  persistence:
    storageClassName: dev-ebs-sc-hot-storage 
logs:
  persistence:
    storageClassName: dev-ebs-sc-hot-storage

[siddjellali]

Up here !
Appreciate.