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content/Docker/Private docker registry.md

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+Suitable to work with [Drone-ci](Drone-ci.md) for hosting private #docker images.
+
+## Sample docker-compose for custom docker registry
+
+This one brings up private docker registry with ui. First you'll need to generate password for it:
+
+```shell
+docker run \
+  --entrypoint htpasswd registry:2 \
+  -Bbn user mypassword > auth/registry.password
+```
+
+```yaml
+version: "3"
+services:
+  registry:
+    container_name: docker__registry
+    image: registry:2
+    ports:
+    - 5000:5000
+    restart: always
+    environment:
+      - REGISTRY_STORAGE_FILESYSTEM_ROOTDIRECTORY=/data
+      - REGISTRY_AUTH=htpasswd
+      - REGISTRY_AUTH_HTPASSWD_REALM=Registry
+      - REGISTRY_AUTH_HTPASSWD_PATH=/auth/registry.password
+      - REGISTRY_HTTP_SECRET=password
+      - REGISTRY_STORAGE_DELETE_ENABLED=true
+    volumes:
+      - ./registry/auth:/auth
+      - ./registry/data:/data
+  ui:
+    container_name: docker__ui
+    image: parabuzzle/craneoperator:latest
+    ports:
+    - 80:80
+    restart: always
+    environment:
+      - REGISTRY_HOST=registry
+      - REGISTRY_PORT=5000
+      - REGISTRY_PROTOCOL=http
+      - ALLOW_REGISTRY_LOGIN=true
+      - REGISTRY_ALLOW_DELETE=true
+      - USERNAME=registry
+      - PASSWORD=password
+```
+
+## Squash layers on registry
+
+Sometimes you need to squash all layers in docker registry to free up disk space.
+
+1. Run this command to mark oldest layers
+
+```shell
+# Try this first
+docker run \
+  --rm anoxis/registry-cli \
+  -r https://registry.url \
+  -l user:password \
+  --delete \
+  --num 2
+
+# Then this 
+docker run -it \
+    -v /path/to/registry/data:/registry \
+    -e REGISTRY_URL=https://registry.url \
+    -e DRY_RUN="false" \
+    -e REGISTRY_AUTH="user:password" \
+    mortensrasmussen/docker-registry-manifest-cleanup
+```
+