Differences

This shows you the differences between two versions of the page.

--- docker [2021/08/27 23:31] – alexk7110
+++ docker [2022/05/28 18:32] (current) – alexk7110
@@ Line 2: / Line 2: @@
 **Docker needs daily or at least weekly** maintenance with the help of the following command:
-  docker system prune -f
+<code bash>
- You should probably put that one on a systemd timer just in case.
+docker system prune -f
+</code>
+You should probably put that one on a systemd timer just in case.
 ===== General maintenance =====
 ==== Prune Unused Images ====
-  docker image prune -a
+<code bash>
+docker image prune -a
+</code>
 ===== Information gathering =====
 ==== Check docker Disk Usage ====
-  docker system df
+<code bash>
-==== List all containers ====
+docker system df
-  docker ps -a
+</code>
+==== List all containers, running or stopped ====
+<code bash>
+docker ps -a
+</code>
 ==== Pretty print the container info ====
-  docker ps --format "table {{.Names}}\t{{.Status}}\t \
+<code bash>
-    {{.Networks}}\t{{.Ports}}\t{{.Size}}"
+docker ps --format "table {{.Names}}\t{{.Status}}\t \
-==== Follow a container's log ====
+  {{.Networks}}\t{{.Ports}}\t{{.Size}}"
-  docker logs -f container_name
+</code>
-==== Information on a network ====
+==== Follow the log of your app ====
-  docker network inspect network_name
+<code bash>
-==== Information on a container ====
+docker logs -f container_name
-  docker container inspect container_name
+</code>
+==== Information on a container ====
+<code bash>
+docker container inspect container_name
+</code>
 ----
 ===== Networking =====
 ==== Check all Networks ====
-  docker network ls
+<code bash>
+docker network ls
+</code>
 ==== Prune Unused Networks ====
-  docker network prune
+<code bash>
+docker network prune
+</code>
+==== Get network information ====
+<code bash>
+docker network inspect network_name
+</code>
 ----
 ===== Container handling =====
 ==== Enter a container ====
-  docker attach mybb_mybb_1
+<code bash>
+docker attach mybb_mybb_1
+</code>
 ==== Show container history ====
-  docker history mybb/mybb:latest
+<code bash>
+docker history mybb/mybb:latest
+</code>
 ==== Get container interactive shell ====
-  docker exec -it mybb_mybb_1 /bin/sh
+<code bash>
+docker exec -it mybb_mybb_1 /bin/sh
-Stopping containers with specific name
+</code>
-  docker container stop $(docker container ls -q --filter name=myapp*)
+==== Stopping containers with specific name ====
+<code bash>
+docker container stop $(docker container ls -q --filter name=myapp*)
+</code>
 ==== Bash function / alias to get a list of Docker image tags: ====
+<code bash>
+dtags () {
+    local image="${1}"
-  dtags () {
+    wget -q https://registry.hub.docker.com/v1/repositories/"${image}"/tags -O - \
-      local image="${1}"
+        | tr -d '[]" ' | tr '}' '\n' | awk -F: '{print $3}'
+}
-      wget -q https://registry.hub.docker.com/v1/repositories/"${image}"/tags -O - \
+</code>
-          | tr -d '[]" ' | tr '}' '\n' | awk -F: '{print $3}'
+==== Find containers from the command line ====
+<code bash>
+docker search ruby --filter="is-official=true"
+</code>
+==== Use the first 4 letters of a container hash to reference it ====
+<code bash>
+docker image inspect f4f4
+</code>
+You only need to reference the first 4 characters of the ID for it to work.
+----
+==== Change the default log policy ====
+By default, Docker captures the standard output (and standard error) of all your containers, and writes them in files using the JSON format.
+So right away we know that Docker is managing its own log files for containers.
+If we look further down in the docs we can see that the max-size option defaults to -1 which means the log’s file size will grow to unlimited size. There’s also the max-file option which defaults to keeping around 1 log file.
+We can change this by editing the daemon.json file which is located in /etc/docker on Linux. On Docker for Windows / Mac you can open up your settings and then goto the “Daemon” tab and flip on the “Advanced” settings.
+Add this into your daemon.json to cap your container logs to 10gb (1,000x 10mb files):
+  "log-driver": "json-file",
+  "log-opts": {
+    "max-size": "10m",
+    "max-file": "1000"
   }
-==== Find containers from the command line ====
-  docker search ruby --filter="is-official=true"
+This will keep 10Gb of log files, so adjust accordingly
+Then restart Docker with ''sudo systemctl restart docker.service'' and you’ll be good to go.
+----
+==== Great site with tips, where some of the above ones are coming from ====
+https://nickjanetakis.com/blog/tag/docker-tips-tricks-and-tutorials

Homelab Troubleshooting

User Tools

Site Tools

Differences

Page Tools