Docker summary

https://github.com/eon01/DockerCheatSheet ---> docker cheat sheet https://forums.docker.com/t/an-error-while-setting-up-container/140117 ---> docker forum for troubleshooting issues

container hold the entire package that is needed to run the application

u can make changes in containder not in image

docker hub, docker engine, host,image

docker naitvely runs in linux and any os

go language

docker is os level virtualisation

docker is paas

cross platform doesnt support

images will run when both os are same

docker daemon

AMI-- amazon machine

container will take all dependencies will take from docker hub

container will take image from docker hub

container image will be shared to testiong for testing purpose

container will not hv os of its own

container will use os resources

continer is like a vm

docker (docker engine) is tool which create this vm

vertical scaling -- cpu and ram increase or decrease

horizontal scaling -- vm scaling

kubernetes will support horizontal scaling

docker file-- instruction file

publish image on docker hub

docker terminology

docker file,image,container,repository,engine

docker image will have app code+software+env+libraries

docker registry -- u can share images

docker hub -- u can store images

as soon as container requires ram it will take from host and will release when task is done

3 ways to create image

take image from docker hub

create image from docker file

create image from existing container

docker file--image--container

daemon will put image locally

docker commands

FROM

RUN

MAINTAINER

COPY

ADD

EXPOSE

WORKDIR

ENTRYPOINT

ENV

CMD

DOCKER COMMANDS PUT IN CAPS

DOCKER -- OPEN SOURCE CENTRALISED PLATFORM desinged to create deploy and run applications

advantages of docker

no pre allocation of ram

less cost

ci efficiency

light weight

it can run on physical hw,virtual hw and cloud

it takes less time to create container

hyper-v enable

virtualization -- enabled

disadv

doesnt hv rich gui

difficult to manage large no.of containers

doesnt provide cross platform compatibility

docker eco system

docker client,hub,image,doemon,engine,

components of docker

doemon,client,host,hub/registry. -----------------------------------------------------------

Table of Contents

Installation

Docker Registries & Repositories

Running Containers

Starting & Stopping Containers

Getting Information about Containers

Networking

Security

Cleaning Docker

Docker Swarm

Notes

The Ultimate Docker Cheat Sheet

Installation

Linux

For more information, see here

curl -sSL https://get.docker.com/ | sh

Mac

For more information, see here

Use this link to download the dmg.

https://download.docker.com/mac/stable/Docker.dmg

Open the downloaded file and follow the installation instructions.

Windows

For more information, see here

Use the msi installer:

https://download.docker.com/win/stable/InstallDocker.msi

Open the downloaded file and follow the installation instructions.

Docker Registries & Repositories

Login to a Registry

docker login

docker login localhost:8080

Logout from a Registry.

docker logout

docker logout localhost:8080

Searching an Image

docker search nginx

docker search --filter stars=3 --no-trunc nginx

Pulling an Image

docker image pull nginx

docker image pull eon01/nginx localhost:5000/myadmin/nginx

Pushing an Image

docker image push eon01/nginx

docker image push eon01/nginx localhost:5000/myadmin/nginx

Running Containers

Create and Run a Simple Container

-Start an ubuntu:latest image

Bind the port 80 from the CONTAINER to port 3000 on the HOST

Mount the current directory to /data on the CONTAINER

Note: on windows you have to change -v ${PWD}:/data to -v "C:\Data":/data

docker container run --name infinite -it -p 3000:80 -v ${PWD}:/data ubuntu:latest

Creating a Container

docker container create -t -i eon01/infinite --name infinite

Running a Container

docker container run -it --name infinite -d eon01/infinite

Renaming a Container

docker container rename infinite infinity

Removing a Container

docker container rm infinite

A container can be removed only after stopping it using docker stop command. To avoid this, add the --rm flag while running the container.

Updating a Container

docker container update --cpu-shares 512 -m 300M infinite

Running a command within a running container

docker exec -it infinite sh

In the example above, bash can replace sh as an alternative (if the above is giving an error).

Starting & Stopping Containers

Starting

docker container start nginx

Stopping

docker container stop nginx

Restarting

docker container restart nginx

Pausing

docker container pause nginx

Unpausing

docker container unpause nginx

Blocking a Container

docker container wait nginx

Sending a SIGKILL

docker container kill nginx

Sending another signal

docker container kill -s HUP nginx

Connecting to an Existing Container

docker container attach nginx

Getting Information about Containers

From Running Containers

Shortest way:

docker ps

Alternative:

docker container ls

From All containers.

docker ps -a

docker container ls -a

Container Logs

docker logs infinite

'tail -f' Containers' Logs

docker container logs infinite -f

Inspecting Containers

docker container inspect infinite

docker container inspect --format '{{ .NetworkSettings.IPAddress }}' $(docker ps -q)

Containers Events

docker system events infinite

Public Ports

docker container port infinite

Running Processes

docker container top infinite

Container Resource Usage

docker container stats infinite

Inspecting changes to files or directories on a container’s filesystem

docker container diff infinite

Managing Images

Listing Images

docker image ls

Building Images

From a Dockerfile in the Current Directory

docker build .

From a Remote GIT Repository

docker build github.com/creack/docker-firefox

Instead of Specifying a Context, You Can Pass a Single Dockerfile in the URL or Pipe the File in via STDIN

docker build - < Dockerfile

docker build - < context.tar.gz

Building and Tagging

docker build -t eon/infinite .

Building a Dockerfile while Specifying the Build Context

docker build -f myOtherDockerfile .

Building from a Remote Dockerfile URI

curl example.com/remote/Dockerfile | docker build -f - .

Removing an Image

docker image rm nginx

Loading a Tarred Repository from a File or the Standard Input Stream

docker image load < ubuntu.tar.gz

docker image load --input ubuntu.tar

Saving an Image to a Tar Archive

docker image save busybox > ubuntu.tar

Showing the History of an Image

docker image history

Creating an Image From a Container

docker container commit nginx

Tagging an Image

docker image tag nginx eon01/nginx

Pushing an Image

docker image push eon01/nginx

Networking

Creating Networks

Creating an Overlay Network

docker network create -d overlay MyOverlayNetwork

Creating a Bridge Network

docker network create -d bridge MyBridgeNetwork

Creating a Customized Overlay Network

docker network create -d overlay \

--subnet=192.168.0.0/16 \

--subnet=192.170.0.0/16 \

--gateway=192.168.0.100 \

--gateway=192.170.0.100 \

--ip-range=192.168.1.0/24 \

--aux-address="my-router=192.168.1.5" --aux-address="my-switch=192.168.1.6" \

--aux-address="my-printer=192.170.1.5" --aux-address="my-nas=192.170.1.6" \ MyOverlayNetwork

Removing a Network

docker network rm MyOverlayNetwork

Listing Networks

docker network ls

Getting Information About a Network

docker network inspect MyOverlayNetwork

Connecting a Running Container to a Network

docker network connect MyOverlayNetwork nginx

Connecting a Container to a Network When it Starts

docker container run -it -d --network=MyOverlayNetwork nginx

Disconnecting a Container from a Network

docker network disconnect MyOverlayNetwork nginx

Exposing Ports

Using Dockerfile, you can expose a port on the container using:

EXPOSE

You can also map the container port to a host port using:

docker run -p $HOST_PORT:$CONTAINER_PORT --name -t e.g.

docker run -p $HOST_PORT:$CONTAINER_PORT --name infinite -t infinite

Security

Guidelines for building secure Docker images

Prefer minimal base images

Dedicated user on the image as the least privileged user

Sign and verify images to mitigate MITM attacks

Find, fix and monitor for open source vulnerabilities

Don’t leak sensitive information to docker images

Use fixed tags for immutability

Use COPY instead of ADD

Use labels for metadata

Use multi-stage builds for small secure images

Use a linter

You can find more nformation on Snyk's 10 Docker Image Security Best Practices blog post.

Cleaning Docker

Removing a Running Container

docker container rm nginx

Removing a Container and its Volume

docker container rm -v nginx

Removing all Exited Containers

docker container rm $(docker container ls -a -f status=exited -q)

Removing All Stopped Containers

docker container rm `docker container ls -a -q`

Removing a Docker Image

docker image rm nginx

Removing Dangling Images

docker image rm $(docker image ls -f dangling=true -q)

Removing all Images

docker image rm $(docker image ls -a -q)

Removing all Untagged Images

docker image rm -f $(docker image ls | grep "^" | awk "{print $3}")

Stopping & Removing all Containers

docker container stop $(docker container ls -a -q) && docker container rm $(docker container ls -a -q)

Removing Dangling Volumes

docker volume rm $(docker volume ls -f dangling=true -q)

Removing all unused (containers, images, networks and volumes)

docker system prune -f

Clean all

docker system prune -a

Docker Swarm

Installing Docker Swarm

curl -ssl https://get.docker.com | bash

Initializing the Swarm

docker swarm init --advertise-addr 192.168.10.1

Getting a Worker to Join the Swarm

docker swarm join-token worker

Getting a Manager to Join the Swarm

docker swarm join-token manager

Listing Services

docker service ls

Listing nodes

docker node ls

Creating a Service

docker service create --name vote -p 8080:80 instavote/vote

Listing Swarm Tasks

docker service ps

Scaling a Service

docker service scale vote=3

Updating a Service

docker service update --image instavote/vote:movies vote

docker service update --force --update-parallelism 1 --update-delay 30s nginx

docker service update --update-parallelism 5--update-delay 2s --image instavote/vote:indent vote

docker service update --limit-cpu 2 nginx

docker service update --replicas=5 nginx --------------------------------------------------------------------------------------------------------------------- https://www.linkedin.com/pulse/navigating-docker-troubleshooting-tips-techniques-victor-mwenda-3un0f ----> important https://www.linkedin.com/today/author/vmwenda?trk=article-ssr-frontend-pulse_more-articles ********************************************** can not open docker #14065 Restart your computer > Go to BIOS and Enable virtualization ********************************************************* Docker cannot run container, returns socket error 99 #8838 Send feedback to Docker Community Slack channels #docker-for-mac or #docker-for-windows. /lifecycle stale https://blog.packagecloud.io/top-five-most-common-issues-with-docker-and-how-to-solve-them/

Table of Contents

Installation

Docker Registries & Repositories

Running Containers

Starting & Stopping Containers

Getting Information about Containers

Networking

Security

Cleaning Docker

Docker Swarm

Notes

The Ultimate Docker Cheat Sheet

Installation

Linux

For more information, see here

curl -sSL https://get.docker.com/ | sh

Mac

For more information, see here

Use this link to download the dmg.

https://download.docker.com/mac/stable/Docker.dmg

Open the downloaded file and follow the installation instructions.

Windows

For more information, see here

Use the msi installer:

https://download.docker.com/win/stable/InstallDocker.msi

Open the downloaded file and follow the installation instructions.

Docker Registries & Repositories

Login to a Registry

docker login

docker login localhost:8080

Logout from a Registry.

docker logout

docker logout localhost:8080

Searching an Image

docker search nginx

docker search --filter stars=3 --no-trunc nginx

Pulling an Image

docker image pull nginx

docker image pull eon01/nginx localhost:5000/myadmin/nginx

Pushing an Image

docker image push eon01/nginx

docker image push eon01/nginx localhost:5000/myadmin/nginx

Running Containers

Create and Run a Simple Container

-Start an ubuntu:latest image

Bind the port 80 from the CONTAINER to port 3000 on the HOST

Mount the current directory to /data on the CONTAINER

Note: on windows you have to change -v ${PWD}:/data to -v "C:\Data":/data

docker container run --name infinite -it -p 3000:80 -v ${PWD}:/data ubuntu:latest

Creating a Container

docker container create -t -i eon01/infinite --name infinite

Running a Container

docker container run -it --name infinite -d eon01/infinite

Renaming a Container

docker container rename infinite infinity

Removing a Container

docker container rm infinite

A container can be removed only after stopping it using docker stop command. To avoid this, add the --rm flag while running the container.

Updating a Container

docker container update --cpu-shares 512 -m 300M infinite

Running a command within a running container

docker exec -it infinite sh

In the example above, bash can replace sh as an alternative (if the above is giving an error).

Starting & Stopping Containers

Starting

docker container start nginx

Stopping

docker container stop nginx

Restarting

docker container restart nginx

Pausing

docker container pause nginx

Unpausing

docker container unpause nginx

Blocking a Container

docker container wait nginx

Sending a SIGKILL

docker container kill nginx

Sending another signal

docker container kill -s HUP nginx

Connecting to an Existing Container

docker container attach nginx

Getting Information about Containers

From Running Containers

Shortest way:

docker ps

Alternative:

docker container ls

From All containers.

docker ps -a

docker container ls -a

Container Logs

docker logs infinite

'tail -f' Containers' Logs

docker container logs infinite -f

Inspecting Containers

docker container inspect infinite

docker container inspect --format '{{ .NetworkSettings.IPAddress }}' $(docker ps -q)

Containers Events

docker system events infinite

Public Ports

docker container port infinite

Running Processes

docker container top infinite

Container Resource Usage

docker container stats infinite

Inspecting changes to files or directories on a container’s filesystem

docker container diff infinite

Managing Images

Listing Images

docker image ls

Building Images

From a Dockerfile in the Current Directory

docker build .

From a Remote GIT Repository

docker build github.com/creack/docker-firefox

Instead of Specifying a Context, You Can Pass a Single Dockerfile in the URL or Pipe the File in via STDIN

docker build - < Dockerfile

docker build - < context.tar.gz

Building and Tagging

docker build -t eon/infinite .

Building a Dockerfile while Specifying the Build Context

docker build -f myOtherDockerfile .

Building from a Remote Dockerfile URI

curl example.com/remote/Dockerfile | docker build -f - .

Removing an Image

docker image rm nginx

Loading a Tarred Repository from a File or the Standard Input Stream

docker image load < ubuntu.tar.gz

docker image load --input ubuntu.tar

Saving an Image to a Tar Archive

docker image save busybox > ubuntu.tar

Showing the History of an Image

docker image history

Creating an Image From a Container

docker container commit nginx

Tagging an Image

docker image tag nginx eon01/nginx

Pushing an Image

docker image push eon01/nginx

Networking

Creating Networks

Creating an Overlay Network

docker network create -d overlay MyOverlayNetwork

Creating a Bridge Network

docker network create -d bridge MyBridgeNetwork

Creating a Customized Overlay Network

docker network create -d overlay \

--subnet=192.168.0.0/16 \

--subnet=192.170.0.0/16 \

--gateway=192.168.0.100 \

--gateway=192.170.0.100 \

--ip-range=192.168.1.0/24 \

--aux-address="my-router=192.168.1.5" --aux-address="my-switch=192.168.1.6" \

--aux-address="my-printer=192.170.1.5" --aux-address="my-nas=192.170.1.6" \ MyOverlayNetwork

Removing a Network

docker network rm MyOverlayNetwork

Listing Networks

docker network ls

Getting Information About a Network

docker network inspect MyOverlayNetwork

Connecting a Running Container to a Network

docker network connect MyOverlayNetwork nginx

Connecting a Container to a Network When it Starts

docker container run -it -d --network=MyOverlayNetwork nginx

Disconnecting a Container from a Network

docker network disconnect MyOverlayNetwork nginx

Exposing Ports

Using Dockerfile, you can expose a port on the container using:

EXPOSE

You can also map the container port to a host port using:

docker run -p $HOST_PORT:$CONTAINER_PORT --name -t e.g.

docker run -p $HOST_PORT:$CONTAINER_PORT --name infinite -t infinite

Security

Guidelines for building secure Docker images

Prefer minimal base images

Dedicated user on the image as the least privileged user

Sign and verify images to mitigate MITM attacks

Find, fix and monitor for open source vulnerabilities

Don’t leak sensitive information to docker images

Use fixed tags for immutability

Use COPY instead of ADD

Use labels for metadata

Use multi-stage builds for small secure images

Use a linter

You can find more nformation on Snyk's 10 Docker Image Security Best Practices blog post.

Cleaning Docker

Removing a Running Container

docker container rm nginx

Removing a Container and its Volume

docker container rm -v nginx

Removing all Exited Containers

docker container rm $(docker container ls -a -f status=exited -q)

Removing All Stopped Containers

docker container rm `docker container ls -a -q`

Removing a Docker Image

docker image rm nginx

Removing Dangling Images

docker image rm $(docker image ls -f dangling=true -q)

Removing all Images

docker image rm $(docker image ls -a -q)

Removing all Untagged Images

docker image rm -f $(docker image ls | grep "^" | awk "{print $3}")

Stopping & Removing all Containers

docker container stop $(docker container ls -a -q) && docker container rm $(docker container ls -a -q)

Removing Dangling Volumes

docker volume rm $(docker volume ls -f dangling=true -q)

Removing all unused (containers, images, networks and volumes)

docker system prune -f

Clean all

docker system prune -a

Docker Swarm

Installing Docker Swarm

curl -ssl https://get.docker.com | bash

Initializing the Swarm

docker swarm init --advertise-addr 192.168.10.1

Getting a Worker to Join the Swarm

docker swarm join-token worker

Getting a Manager to Join the Swarm

docker swarm join-token manager

Listing Services

docker service ls

Listing nodes

docker node ls

Creating a Service

docker service create --name vote -p 8080:80 instavote/vote

Listing Swarm Tasks

docker service ps

Scaling a Service

docker service scale vote=3

Updating a Service

docker service update --image instavote/vote:movies vote

docker service update --force --update-parallelism 1 --update-delay 30s nginx

docker service update --update-parallelism 5--update-delay 2s --image instavote/vote:indent vote

docker service update --limit-cpu 2 nginx

docker service update --replicas=5 nginx Inspect volume

Docker networking is a fascinating topic. When one knows how to use Docker, then knowing it's networking and other internals helps even more.

In this document, I have explained:

different networking modes available in docker,

the mechanisms of service discovery,

and procedure to join containers to each other for troubleshooting.

Note: The examples are from a docker host running Fedora Linux 31, and Docker Engine 19.03.8 .

The following networks are available to you by default, when you install docker on your computer.

Bridge - NAT - docker0

Host - Uses host network

None - Isolated / no networking

Other Docker networks available to you are the following, but are not covered in this document.

Overlay - Swarm mode

Macvlan - Legacy applications needing direct connection to physical network

3rd party network plugins

Note: In case you are wondering, in very simple terms, a software bridge is just another name for a (software) network switch!

At the highest level, Docker networking comprises three major components:

The Container Network Model (CNM)

libnetwork

Drivers

at a high level, it defines three major building blocks:

Sandboxes

Endpoints

Networks

A network sandbox, an isolated networking stack inside the container which may support multiple individual networks through endpoints. It includes; Ethernet

interfaces, ports, routing tables, and DNS config.

A container endpoint, specified by the CNM and attached to the network sandbox, is an interface paired with an interface on a network, allowing the container to

connect to that particular network. Endpoints are virtual network interfaces (E.g. veth). Like normal network interfaces, they’re responsible for making

connections. In the case of the CNM, it’s the job of the endpoint to connect a sandbox to a network.

Bridge

A Bridge is a default Docker network that is present on any Linux host which runs a Docker Engine.

Understanding correlated terms:

A bridge is a Docker network

A bridge is also a Docker network driver/template, which creates a bridge network

docker0 is the kernel building block that is used in implementing the bridge network

Advantages:

Optimizes the performance.

Handles a large range of ports.

Does not require network address translation (NAT).

Does not require “userland-proxy” for each port.

Features:

An overlay network is used to manage swarm and service-related traffic.

The Docker daemon host network and ports are used to send data for individual swarm service.

network host: This is passed with command docker service create to use a host network for a swarm service.

https://github.com/kaan-keskin/introduction-to-docker/blob/main/ContainerNetworking.md

Image also don’t contain a kernel — all containers running on a Docker host share access to the host’s kernel. For these reasons, we sometimes say images contain

just enough operating system (usually just OS-related files and filesystem objects).

Note: Hyper-V containers run a single container inside of a dedicated lightweight VM. The container leverages the kernel of the OS running inside the VM.

Windows-based Docker hosts this is C:\ProgramData\docker\windowsfilter

$ docker image ls

docker info

Image registries

The most common registry is Docker Hub (https://hub.Docker.com)

Image naming and tagging

$ docker image pull :

Filtering the output of docker image ls

The format of filter flag is a key-value pair. Docker provides the --filter flag to filter the list of images returned by docker image ls.

Filter option is used in docker images to filter:

Images that are not tagged.

Images that are labelled.

Images by time.

Images by reference.

The following example will only return dangling images.

$ docker image ls --filter dangling=true

You can delete all dangling images on a system with the docker image prune command. If you add the -a flag, Docker will also remove all unused images (those not in

use by any containers).

Docker currently supports the following filters:

dangling: Accepts true or false, and returns only dangling images (true), or non-dangling images (false).

before: Requires an image name or ID as argument, and returns all images created before it.

since: Same as above, but returns images created after the specified image.

label: Filters images based on the presence of a label or label and value. The docker image ls command does not display labels in its output.

ou can also use the --format flag to format output using Go templates.

Format option is used in docker image to filter:

Image ID

Image repository

Image tag

Image digest

Image disk size

Time at which the image was created

Time elapsed since the creation of the image

$ docker image ls --format "{{.Size}}"

$ docker search alpine

The docker history command is another way of inspecting an image and seeing layer data. However, it shows the build history of an image and is not a strict list of

layers in the final image. For example, some Dockerfile instructions (“ENV”, “EXPOSE”, “CMD”, and “ENTRYPOINT”) add metadata to the image and do not result in

permanent layers being created.

All Docker images start with a base layer, and as changes are made and new content is added, new layers are added on top.

Good use cases for volumes

Volumes are the preferred way to persist data in Docker containers and services. Some use cases for volumes include:

Sharing data among multiple running containers. If you don't explicitly create it, a volume is created the first time it is mounted into a container. When that

container stops or is removed, the volume still exists. Multiple containers can mount the same volume simultaneously, either read-write or read-only. Volumes are

only removed when you explicitly remove them.

When the Docker host is not guaranteed to have a given directory or file structure. Volumes help you decouple the configuration of the Docker host from the

container runtime.

When you want to store your container's data on a remote host or a cloud provider, rather than locally.

When you need to back up, restore, or migrate data from one Docker host to another, volumes are a better choice. You can stop containers using the volume, then

back up the volume's directory (such as /var/lib/docker/volumes/).

When your application requires high-performance I/O on Docker Desktop. Volumes are stored in the Linux VM rather than the host, which means that the reads and

writes have much lower latency and higher throughput.

When your application requires fully native file system behavior on Docker Desktop. For example, a database engine requires precise control over disk flushing to

guarantee transaction durability. Volumes are stored in the Linux VM and can make these guarantees, whereas bind mounts are remoted to macOS or Windows, where the

file systems behave slightly differently.

Good use cases for bind mounts

In general, you should use volumes where possible. Bind mounts are appropriate for the following types of use case:

Sharing configuration files from the host machine to containers. This is how Docker provides DNS resolution to containers by default, by mounting /etc/resolv.conf

from the host machine into each container.

Sharing source code or build artifacts between a development environment on the Docker host and a container. For instance, you may mount a Maven target/ directory

into a container, and each time you build the Maven project on the Docker host, the container gets access to the rebuilt artifacts.

If you use Docker for development this way, your production Dockerfile would copy the production-ready artifacts directly into the image, rather than relying on a

bind mount.

When the file or directory structure of the Docker host is guaranteed to be consistent with the bind mounts the containers require.

Good use cases for tmpfs mounts

tmpfs mounts are best used for cases when you do not want the data to persist either on the host machine or within the container. This may be for security reasons

or to protect the performance of the container when your application needs to write a large volume of non-persistent state data.

Tips for using bind mounts or volumes

If you use either bind mounts or volumes, keep the following in mind:

If you mount an empty volume into a directory in the container in which files or directories exist, these files or directories are propagated (copied) into the

volume. Similarly, if you start a container and specify a volume which does not already exist, an empty volume is created for you. This is a good way to pre-

populate data that another container needs.

If you mount a bind mount or non-empty volume into a directory in the container in which some files or directories exist, these files or directories are obscured

by the mount, just as if you saved files into /mnt on a Linux host and then mounted a USB drive into /mnt. The contents of /mnt would be obscured by the contents

of the USB drive until the USB drive was unmounted. The obscured files are not removed or altered, but are not accessible while the bind mount or volume is mounted. ************************************************

Volumes

Volumes are the preferred mechanism for persisting data generated by and used by Docker containers. While bind mounts are dependent on the directory structure and

OS of the host machine, volumes are completely managed by Docker. Volumes have several advantages over bind mounts:

Volumes are easier to back up or migrate than bind mounts.

You can manage volumes using Docker CLI commands or the Docker API.

Volumes work on both Linux and Windows containers.

Volumes can be more safely shared among multiple containers.

Volume drivers let you store volumes on remote hosts or cloud providers, encrypt the contents of volumes, or add other functionality.

New volumes can have their content pre-populated by a container.

Volumes on Docker Desktop have much higher performance than bind mounts from Mac and Windows hosts. ************************************************************

Bind mounts

Bind mounts have been around since the early days of Docker. Bind mounts have limited functionality compared to volumes. When you use a bind mount, a file or

directory on the host machine is mounted into a container. The file or directory is referenced by its absolute path on the host machine. By contrast, when you use

a volume, a new directory is created within Docker's storage directory on the host machine, and Docker manages that directory's contents.

The file or directory does not need to exist on the Docker host already. It is created on demand if it does not yet exist. Bind mounts are very performant, but

they rely on the host machine's filesystem having a specific directory structure available. If you are developing new Docker applications, consider using named

volumes instead. You can't use Docker CLI commands to directly manage bind mounts. *******************************************************************************

Volumes and bind mounts let you share files between the host machine and container so that you can persist data even after the container is stopped.

tmpfs

If you're running Docker on Linux, you have a third option: tmpfs mounts. When you create a container with a tmpfs mount, the container can create files outside

the container's writable layer.

This is useful to temporarily store sensitive files that you don't want to persist in either the host or the container writable layer

As opposed to volumes and bind mounts, a tmpfs mount is temporary, and only persisted in the host memory. When the container stops, the tmpfs mount is removed, and

files written there won't be persisted.

Limitations of tmpfs mounts

Unlike volumes and bind mounts, you can't share tmpfs mounts between containers.

This functionality is only available if you're running Docker on Linux.

Setting permissions on tmpfs may cause them to reset after container restart. In some cases setting the uid/gid can serve as a workaround. *************************************************************************

Container size on disk

To view the approximate size of a running container, you can use the docker ps -s command. Two different columns relate to size.

https://docs.docker.com/storage/storagedriver/#storage-drivers-versus-docker-volumes **********************************************************

I was able to solve this by making sure the docker daemon was running with real-time scheduler enabled:

failed to write to cpu.rt_runtime_us #3046 *****************************************************

docker should fail if config file is invalid #5075

error: docker info not found when we run docker info command

docker version Client: Version: 26.1.2 API version: 1.44 (downgraded from 1.45) Go version: go1.21.10 Git commit: 211e74b Built: Wed May 8 13:59:48 2024 OS/Arch: linux/arm64 Context: default docker info not relevant

mapping a container port to multiple host ports doesn't work in host mode #5020

solution

1.create a compose file foo.yml

2.deploy the services

docker stack deploy -c foo.yml foo

inspect the service

docker ps | grep foo

example output with the 7500 mapping missing 3.

Expected behavior

Both ports 7500 and 7501 should have been mapped, but only the last one was. Reproduce create a compose file foo.yml version: "3.4" services: nginx: image: nginx ports: - target: 80 published: 7500 protocol: tcp mode: host - target: 80 published: 7501 protocol: tcp mode: host - target: 90 published: 7502 protocol: tcp mode: host deploy the services docker stack deploy -c foo.yml foo inspect the service docker ps | grep foo example output with the 7500 mapping missing e52e785d43ab nginx:latest "/docker-entrypoint.…" 3 minutes ago Up 3 minutes 0.0.0.0:7501->80/tcp, :::7501->80/tcp, 0.0.0.0:7502->90/tcp, :::7502->90/tcp foo_nginx.1.ynapf1jho2sg2jib4391j1tej Expected behavior Both ports 7500 and 7501 should have been mapped, but only the last one was. docker version Client: Docker Engine - Community Version: 26.0.0 API version: 1.45 Go version: go1.21.8 Git commit: 2ae903e Built: Wed Mar 20 15:18:12 2024 OS/Arch: linux/amd64 Context: default Server: Docker Engine - Community Engine: Version: 26.0.0 API version: 1.45 (minimum version 1.24) Go version: go1.21.8 Git commit: 8b79278 Built: Wed Mar 20 15:18:12 2024 OS/Arch: linux/amd64 Experimental: false containerd: Version: 1.6.28 GitCommit: ae07eda36dd25f8a1b98dfbf587313b99c0190bb runc: Version: 1.1.12 GitCommit: v1.1.12-0-g51d5e94 docker-init: Version: 0.19.0 GitCommit: de40ad0 docker info Client: Docker Engine - Community Version: 26.0.0 Context: default Debug Mode: false Plugins: buildx: Docker Buildx (Docker Inc.) Version: v0.13.1 Path: /usr/libexec/docker/cli-plugins/docker-buildx compose: Docker Compose (Docker Inc.) Version: v2.25.0 Path: /usr/libexec/docker/cli-plugins/docker-compose scan: Docker Scan (Docker Inc.) Version: v0.23.0 Path: /usr/libexec/docker/cli-plugins/docker-scan Server: Containers: 97 Running: 39 Paused: 0 Stopped: 58 Images: 55 Server Version: 26.0.0 Storage Driver: overlay2 Backing Filesystem: extfs Supports d_type: true Using metacopy: false Native Overlay Diff: true userxattr: false Logging Driver: json-file Cgroup Driver: systemd Cgroup Version: 2 Plugins: Volume: local Network: bridge host ipvlan macvlan null overlay Log: awslogs fluentd gcplogs gelf journald json-file local splunk syslog Swarm: active NodeID: rnkuw1h18qfave5s02qrpil4g Is Manager: true ClusterID: ibv4nqt659hdxmqv32gkk7a49 Managers: 1 Nodes: 1 Default Address Pool: 10.0.0.0/8 SubnetSize: 24 Data Path Port: 4789 Orchestration: Task History Retention Limit: 5 Raft: Snapshot Interval: 10000 Number of Old Snapshots to Retain: 0 Heartbeat Tick: 1 Election Tick: 10 Dispatcher: Heartbeat Period: 5 seconds CA Configuration: Expiry Duration: 3 months Force Rotate: 0 Autolock Managers: false Root Rotation In Progress: false Node Address: 172.20.3.61 Manager Addresses: 172.20.3.61:2377 Runtimes: runc io.containerd.runc.v2 Default Runtime: runc Init Binary: docker-init containerd version: ae07eda36dd25f8a1b98dfbf587313b99c0190bb runc version: v1.1.12-0-g51d5e94 init version: de40ad0 Security Options: apparmor seccomp Profile: builtin cgroupns Kernel Version: 5.10.0-28-amd64 Operating System: Debian GNU/Linux 11 (bullseye) OSType: linux Architecture: x86_64 CPUs: 12 Total Memory: 15.53GiB Name: cldev10 ID: TRKH:KEBO:ESTR:OKOG:NACA:LTD6:RN34:5TFK:TJCM:WE44:LDXK:A6HY Docker Root Dir: /var/lib/docker Debug Mode: false Experimental: false Insecure Registries: aadocker01.as-i.com:5000 127.0.0.0/8 Live Restore Enabled: false **********************************************

can not open docker #14065

Restart your computer > Go to BIOS and Enable virtualization *********************************************************

Docker cannot run container, returns socket error 99 #8838

Send feedback to Docker Community Slack channels #docker-for-mac or #docker-for-windows.

/lifecycle stale

https://blog.packagecloud.io/top-five-most-common-issues-with-docker-and-how-to-solve-them/ ***********************************************************************************

https://www.linkedin.com/pulse/navigating-docker-troubleshooting-tips-techniques-victor-mwenda-3un0f ----> important

https://www.linkedin.com/today/author/vmwenda?trk=article-ssr-frontend-pulse_more-articles ******************************************************************

azure billing,subscription

Log Analytics

Azure Monitor.

scale set

av set

av zone

load balancer

auto scaling

networking

deployment

https://refine.dev/blog/docker-volumes/#brief-introduction-to-docker