Question 278832 in PostgreSQL Question posted in
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Postgresql – Can not run run command on Postgres container from bash script

I am trying to run a sql script upon a postgreSQL container in k8S
If i run my commands in the command line one by one , it works.
However if i run the script file it does not trying to connect to port 8080.
There is nothing running on port 8080 and my postgres pod uses the default port of 5432
I can connect to my pod if i run the commands one by one, i can connect to the sql pod with the PostgreAdmin, but somehow i get this error , when i run the script:

Error

sanzor@DESKTOP-GOMS8S8:~/NovaWebsocketServer$ ./start.sh
got here
The connection to the server localhost:8080 was refused - did you specify the right host or port?

script.sh

#!/bin/bash

# Define the PostgreSQL username and password
PGUSER="admin"
PGPASSWORD="test123"

# Define the SQL script path
SQL_SCRIPT_PATH="/home/sanzor/NovaWebsocketServer/resources/tables.pgsql"

# Get the name of the PostgreSQL pod
POSTGRES_POD=$(kubectl get pods -l app=postgres -o jsonpath='{.items[0].metadata.name}')
echo "got here"
# Use cat to insert the SQL script content into psql in the PostgreSQL pod
cat "$SQL_SCRIPT_PATH" | sudo -S kubectl exec -it "$POSTGRES_POD" -- psql -U "$PGUSER" -d postgresdb

# Exit the script
exit

Pod data

sanzor@DESKTOP-GOMS8S8:~/NovaWebsocketServer$ kubectl get pods
NAME                        READY   STATUS    RESTARTS   AGE
postgres-7b9fb8d6c5-5s85s   1/1     Running   69         111d

Pod description

sanzor@DESKTOP-GOMS8S8:~/NovaWebsocketServer$ kubectl describe pod postgres-7b9fb8d6c5-5s85s
Name:         postgres-7b9fb8d6c5-5s85s
Namespace:    default
Priority:     0
Node:         docker-desktop/192.168.65.4
Start Time:   Sat, 15 Jul 2023 16:39:59 +0300
Labels:       app=postgres
              pod-template-hash=7b9fb8d6c5
Annotations:  <none>
Status:       Running
IP:           10.1.2.108
IPs:
  IP:           10.1.2.108
Controlled By:  ReplicaSet/postgres-7b9fb8d6c5
Containers:
  postgres:
    Container ID:   docker://661876a876e9e2e7be10c8c36f42804a9cb5de0a573d3352c7bd38b1b1043934
    Image:          postgres:10.1
    Image ID:       docker-pullable://postgres@sha256:3f4441460029e12905a5d447a3549ae2ac13323d045391b0cb0cf8b48ea17463
    Port:           5432/TCP
    Host Port:      0/TCP
    State:          Running
      Started:      Sat, 04 Nov 2023 07:45:17 +0200
    Last State:     Terminated
      Reason:       Error
      Exit Code:    255
      Started:      Fri, 03 Nov 2023 15:38:42 +0200
      Finished:     Sat, 04 Nov 2023 07:45:03 +0200
    Ready:          True
    Restart Count:  69
    Environment Variables from:
      postgres-config  ConfigMap  Optional: false
    Environment:       <none>
    Mounts:
      /var/lib/postgresql/data from postgredb (rw)
      /var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-wdg6m (ro)
Conditions:
  Type              Status
  Initialized       True 
  Ready             True 
  ContainersReady   True 
  PodScheduled      True 
Volumes:
  postgredb:
    Type:       PersistentVolumeClaim (a reference to a PersistentVolumeClaim in the same namespace)
    ClaimName:  postgres-pv-claim
    ReadOnly:   false
  kube-api-access-wdg6m:
    Type:                    Projected (a volume that contains injected data from multiple sources)
    TokenExpirationSeconds:  3607
    ConfigMapName:           kube-root-ca.crt
    ConfigMapOptional:       <nil>
    DownwardAPI:             true
QoS Class:                   BestEffort
Node-Selectors:              <none>
Tolerations:                 node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
                             node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
  Type    Reason          Age   From     Message
  ----    ------          ----  ----     -------
  Normal  SandboxChanged  49m   kubelet  Pod sandbox changed, it will be killed and re-created.
  Normal  Pulled          49m   kubelet  Container image "postgres:10.1" already present on machine
  Normal  Created         49m   kubelet  Created container postgres
  Normal  Started         49m   kubelet  Started container postgres
Tags:

2

Answers


  1. 0

    The The connection to the server localhost:8080 was refused - did you specify the right host or port? seems to be related to kubectl trying to read in the contents of cat "$SQL_SCRIPT_PATH" — the tables.pgsql is getting passed to kubectl and ends there, and doesn’t make it all the way to psql. I believe if you call kubectl cluster-info you should get something like:

    root@sqa03:~# kubectl cluster-info
Kubernetes master is running at http://localhost:8080

    So when you cat "$SQL_SCRIPT_PATH" | sudo -S kubectl exec -it ..., it’s kubectl erroring out because it doesn’t know what to do with the contents of tables.pgsql

    Rather than cat the file into sudo kubectl ... I would recommend copying the file into the pod with kubectl cp $SQL_SCRIPT_PATH <namespace>/<pod>:/path/to/tables.pgsql, then tell the pod to call psql -f /path/to/tables.pgsql -U "$PGUSER" -d postgresdb`.

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  2. 0

    If you run sudo kubectl config get-contexts and see no cluster is listed, you need to copy the current user’s ~/.kube/config to the root user’s home directory first.

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