From b8d7b8a4025373b6fe17a81a4cf2fc917a6e91ea Mon Sep 17 00:00:00 2001
From: Eduard Tolosa <tolosaeduard@gmail.com>
Date: Fri, 21 Feb 2025 07:41:23 +0000
Subject: [PATCH] Initial commit.

---
 fly-to-podman.sh | 139 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 139 insertions(+)
 create mode 100644 fly-to-podman.sh

diff --git a/fly-to-podman.sh b/fly-to-podman.sh
new file mode 100644
index 0000000..5b336e1
--- /dev/null
+++ b/fly-to-podman.sh
@@ -0,0 +1,139 @@
+#!/bin/bash
+# This script is used to migrate from Docker to Podman
+
+# Migrate images
+migrate_images() {
+    echo "Migrating Docker images to Podman..."
+    # Get a list of all Docker images (name:tag)
+    docker images --format "{{.Repository}}:{{.Tag}}" | while read -r image; do
+        # Skip <none>:<none> images
+        if [[ "$image" == "<none>:<none>" ]]; then
+            continue
+        fi
+
+        # Replace slashes in repository names with underscores for filenames
+        filename=$(echo "$image" | tr '/' '_').tar
+
+        echo "Exporting $image..."
+        docker save -o "$filename" "$image" &&
+            podman load -i "$filename" &&
+            echo "Image $image migrated to Podman" || echo "Failed to migrate image $image"
+
+        # Remove temporary file
+        rm -f "$filename"
+    done
+}
+
+# Migrate volumes
+migrate_volumes() {
+    echo "Migrating Docker volumes to Podman..."
+    # Get the path to the Podman volumes directory
+    PODMAN_VOLUMES_PATH=$(podman info --format json | jq -r '.store.volumePath')
+    DOCKER_VOLUMES_PATH="/var/lib/docker/volumes"
+
+    for volume in $(docker volume ls --format json | jq -r '.Name'); do
+        echo "Migrating volume: $volume"
+        podman volume create "$volume" &&
+            sudo rsync -a "$DOCKER_VOLUMES_PATH/$volume/_data/" "$PODMAN_VOLUMES_PATH/$volume/_data"
+    done
+}
+
+# Migrate containers
+migrate_containters() {
+    echo "Migrating Docker containers to Podman..."
+    for container in $(docker container ls -a --format json | jq -r '.Names'); do
+        # Convert container name to lowercase
+        container_lc=$(echo "$container" | tr '[:upper:]' '[:lower:]')
+        # Tag for the image to be created from the container
+        MIGRATION_CONTAINER_TAG="podman.local/${container_lc}-to-podman:latest"
+        # Get Running status from Docker
+        WAS_RUNNING=$(docker container inspect -f '{{.State.Running}}' "$container")
+        # Get RestartPolicy from Docker
+        RESTART_POLICY=$(docker inspect -f '{{.HostConfig.RestartPolicy.Name}}' "$container")
+
+        # Pass the restart policy to Podman
+        case "$RESTART_POLICY" in
+        "no") PODMAN_RESTART="" ;;
+        "always") PODMAN_RESTART="--restart=always" ;;
+        "unless-stopped") PODMAN_RESTART="--restart=unless-stopped" ;;
+        "on-failure") PODMAN_RESTART="--restart=on-failure" ;;
+        *) PODMAN_RESTART="" ;;
+        esac
+
+        echo "Processing container: $container"
+
+        # Commit container to an image. It lets us start a new container with the _same_ state and add additional options
+        docker commit "$container" "$MIGRATION_CONTAINER_TAG" &&
+            docker save -o "$container_lc".tar "$MIGRATION_CONTAINER_TAG" &&
+            podman load -i "$container_lc".tar || {
+            echo "Failed to migrate image for $container"
+            continue
+        }
+
+        # Extract volume/bind mount information from Docker container
+        MOUNT_OPTS=""
+        while read -r mount; do
+            MOUNT_TYPE=$(echo "$mount" | jq -r '.Type')
+            SOURCE=$(echo "$mount" | jq -r '.Source')
+            DESTINATION=$(echo "$mount" | jq -r '.Destination')
+            READ_WRITE=$(echo "$mount" | jq -r '.RW')
+
+            # Pass the RW/RO setting to Podman
+            if [[ "$READ_WRITE" == "true" ]]; then
+                MODE="rw"
+            else
+                MODE="ro"
+            fi
+
+            if [[ "$MOUNT_TYPE" == "volume" ]]; then
+                # Use :U to ensure right permissions inside the container.
+                # It tells Podman to use the correct host UID and GID based on the UID and GID within the <<container|pod>>
+                MODE+=",U"
+                # Attach existing named volume
+                VOLUME_NAME=$(echo "$mount" | jq -r '.Name')
+                MOUNT_OPTS+=" -v $VOLUME_NAME:$DESTINATION:$MODE"
+            elif [[ "$MOUNT_TYPE" == "bind" ]]; then
+                # Use :Z if you're using SELinux to ensure right permissions inside the container
+                # MODE+=",Z"
+                # Ensure the source path exists before mounting
+                [[ -e "$SOURCE" ]] && MOUNT_OPTS+=" -v $SOURCE:$DESTINATION:$MODE"
+            fi
+        done < <(docker inspect "$container" | jq -c '.[0].Mounts[]')
+
+        # Run the container with the same name and mounts, including RW/RO options
+        podman run -d --name "$container" $PODMAN_RESTART "$MOUNT_OPTS" "$MIGRATION_CONTAINER_TAG" &&
+            echo "Container $container migrated successfully" ||
+            echo "Failed to migrate container: $container"
+
+        # Stop the container if this was not running, this allow us to keep the container ready to `podman container start $container`
+        if [[ "$WAS_RUNNING" == "false" ]]; then
+            podman stop "$container"
+        fi
+    done
+}
+
+# Process arguments
+case "$1" in
+images)
+    migrate_images
+    ;;
+volumes)
+    migrate_volumes
+    ;;
+containers)
+    migrate_containters
+    ;;
+full)
+    migrate_images
+    migrate_volumes
+    migrate_containters
+    ;;
+*)
+    echo "Usage: $0 {images|volumes|containers|full}"
+    echo -e "\timages: Migrate Docker images to Podman"
+    echo -e "\tvolumes: Migrate Docker volumes to Podman"
+    echo -e "\tcontainers: Migrate Docker containers to Podman"
+    echo -e "\tfull: Migrate Docker images, volumes, and containers to Podman"
+    exit 1
+    ;;
+esac