Gold Ayan's Tinker Garage

I thought of learning postgres. Instead of installing in the host machine how difficult it would be to spin up the container. Let's find out.

Installing podman

  • I installed the podman that is available in ubuntu repo
sudo apt install podman
  • Note: you won't get the latest podman

Let's check podman

  • Let's pull the postgres container
podman pull postgres
  • Nothing happened, so i tried podman search postgres which gave me the following error
ERRO[0000] User-selected graph driver "vfs" overwritten by graph driver "overlay" from database - delete libpod local files to resolve
  • After some googling and github issue surfing i found fuse-overlayfs is missing in my system, which caused the above error
sudo apt install fuse-overlayfs

Pod initialize

  • we will spin the container inside the pod, later if we want we can migrate it to kubernetes :p.
  • Creating the pod
podman pod create --name postgres-pod -p 9876:80
  • Install postgres in the pod
podman run --pod=postgres-pod \
-v ~/Documents/Postgres:/var/lib/postgresql/data \
-e POSTGRES_PASSWORD=goldayan \
-e POSTGRES_USER=goldayan \
--name db \
-d postgres
  • I got the following error short-name "postgres" did not resolve to an alias and no unqualified-search registries are defined in "/etc/containers/registries.conf"
  • I found the answer for this issue in the following stackoverflow answer, https://unix.stackexchange.com/questions/701784/podman-no-longer-searches-dockerhub-error-short-name-did-not-resolve-to-an
  • NOTE: RISK OF USING UNQUALIFIED IMAGE NAMES We recommend always using fully qualified image names including the registry server (full dns name), namespace, image name, and tag (e.g., registry.redhat.io/ubi8/ubi:latest). Pulling by digest (i.e., quay.io/repository/name@digest) further eliminates the ambiguity of tags
  • Run the following command, let's replace postgres with docker.io/postgres.
  • Telling it to fetch the image from docker.io registery.
podman run --pod=postgres-pod \
-v ~/Documents/Postgres:/var/lib/postgresql/data \
-e POSTGRES_PASSWORD=goldayan \
-e POSTGRES_USER=goldayan \
--name db \
-d docker.io/postgres
  • pgadmin web version
podman run --pod=postgres-pod \
-e 'PGADMIN_DEFAULT_EMAIL=me@goldayan.in' \
-e 'PGADMIN_DEFAULT_PASSWORD=goldayan' \
--name pgadmin \  # name the container
-d docker.io/dpage/pgadmin4   # the image we are pulling
  • Login to pgadmin using the following url localhost:9876
  • Enter the creds, same as what you given for PGADMINDEFAULTEMAIL and PGADMINDEFAULTPASSWORD when running pgadmin container
  • After SignIn, Press add new server
  • Give any name for the server and for the connection type localhost for server and 5432 as port number.
  • Maintenance database will be postgres by default.
  • Username and password will be what you specified in the POSTGRESUSER and POSTGRESPASSWORD when running postgres container.
  • Press save.

Pod commands

  • Status of the pod
podman pod stats postgres-pod
  • Pause and unpause the pod
podman pod pause postgres-pod
podman pod unpause postgres-pod
  • Start and stop the pod
podman pod start postgres-pod
podman pod stop postgres-pod
  • Last but not least, generate kubeconfig from the pod
podman generate kube postgres-pod >> postgres-pod-conf.yml

Log into postgres container

  • we will log into the postgres container and use the psql command
podman exec -it db bash
  • psql command to connect to the db
psql -U goldayan
  • we use goldayan because that is the username we used previously during creating postgres container.

When importing csv file in pgadmin

  • Before I upload the csv file i removed the header
  • Select the upload csv file then press import, voila… imported.

Reset the podman [WARN]

  • To delete all the images, containers, pods and cache
podman system reset
  • Just delete containers
sudo rm -rf ~/.local/share/containers/