How to update docker container

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Как обновить образ и контейнер Docker до последней версии

3 минуты чтения

Образы Docker в работающем контейнере не обновляются автоматически. После того, как вы использовали образ для создания контейнера, он продолжает работать с этой версией даже после выхода новых выпусков.

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Вместе и с нуля пройдем все этапы проектирования, администрирования, резервирования и масштабирования БД с использованием PostgreSQL, MS SQL и MySQL, чтобы получить оплачиваемые навыки DBA (администратора БД).

Рекомендуется запускать контейнеры из последнего образа Docker, если у вас нет особой причины использовать более старую версию.

В этом руководстве вы узнаете, как обновить образ и контейнер Docker до последней версии.

Обнолвение образа и контейнера Docker до последней версии

Примечание. В этом руководстве используется пример запуска контейнера MySQL Docker, чтобы проиллюстрировать, как обновить образ и контейнер Docker до последней версии.

Шаг 1. Проверьте текущую версию

Убедитесь, что у вас устаревший образ, выведя список образов в вашей системе с помощью команды:

Поэтому, если у вас есть контейнер, работающий с этим образом, лучше его обновить.

Шаг 2. Скачайте новейший образ

Загрузите более новую версию образа с помощью команды docker pull :

Например, чтобы получить последний образ mysql, вы должны запустить:

Шаг 3. Запустите новый обновленный контейнер

После того, как вы загрузили последний образ Docker, вам необходимо остановить и удалить старый контейнер. Затем создайте новый с последним образом.

1. Найдите имя запущенного контейнера с устаревшим образом, перечислив контейнеры в системе:

В этом примере на выходе показан контейнер с образом mysql / mysql-server: 5.7.31.

2. Остановите и удалите существующий контейнер, чтобы вы могли запустить новый под тем же именем:

3. Воссоздайте контейнер с помощью команды docker run и желаемой конфигурации, используя обновленный образ Docker:

Например, чтобы запустить обновленный контейнер MySQL, вы должны запустить:

4. Вы можете проверить, обновлен ли ваш контейнер последней версией образа Docker, таким образом:

Таким образом, вы должны были успешно обновить свой контейнер Docker.

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docker update

Estimated reading time: 4 minutes

Update configuration of one or more containers

Usage

Refer to the options section for an overview of available OPTIONS for this command.

Description

The docker update command dynamically updates container configuration. You can use this command to prevent containers from consuming too many resources from their Docker host. With a single command, you can place limits on a single container or on many. To specify more than one container, provide space-separated list of container names or IDs.

The docker update and docker container update commands are not supported for Windows containers.

For example uses of this command, refer to the examples section below.

Options

Examples

The following sections illustrate ways to use this command.

Update a container’s cpu-shares

To limit a container’s cpu-shares to 512, first identify the container name or ID. You can use docker ps to find these values. You can also use the ID returned from the docker run command. Then, do the following:

Update a container with cpu-shares and memory

To update multiple resource configurations for multiple containers:

Update a container’s kernel memory constraints

For example, if you started a container with this command:

You can update kernel memory while the container is running:

If you started a container without kernel memory initialized:

Update a container’s restart policy

You can change a container’s restart policy on a running container. The new restart policy takes effect instantly after you run docker update on a container.

To update restart policy for one or more containers:

Note that if the container is started with “—rm” flag, you cannot update the restart policy for it. The AutoRemove and RestartPolicy are mutually exclusive for the container.

Docker: How to update your container when your code changes

I am trying to use Docker for local development. The problem is that when I make a change to my code, I have to run the following commands to see the updates locally:

That’s quite a mouthful, and takes a while. (Possibly I could make it into a bash script, but do you think that is a good idea?)

My real question is: Is there a command that I can use (even manually each time) that will update the image & container? Or do I have to go through the entire workflow above every time I make a change in my code?

Dockerfile

docker-compose.yml

3 Answers 3

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Even though there are multiple good answers to this question, I think they missed the point, as the OP is asking about the local dev environment. The command I usually use in this situation is:

If there aren’t any errors in Dockerfile, it should rebuild all the images before bringing up the stack. It could be used in a shell script if needed.

If you need to tear down the whole stack, you can have another script:

NOTE: In some cases, sudo might not be needed to run the command.

When a docker image is build the artifacts are already copied and no new change can reflect until you rebuild the image.

If it is only for local development, then you can leverage volume sharing to update code inside container in runtime. The idea is to share your app/repo directory on host machine with /usr/src/app (as per your Dockerfile) and with this approach your code (and new changes) will be appear on both host and the running container.

Also, you will need to restart the server on every change and for this you can run your app using nodemon (as it watches for changes in code and restarts the server)

How to upgrade docker container after its image changed

Let’s say I have pulled the official mysql:5.6.21 image.

I have deployed this image by creating several docker containers.

These containers have been running for some time until MySQL 5.6.22 is released. The official image of mysql:5.6 gets updated with the new release, but my containers still run 5.6.21.

How do I propagate the changes in the image (i.e. upgrade MySQL distro) to all my existing containers? What is the proper Docker way of doing this?

14 Answers 14

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After evaluating the answers and studying the topic I’d like to summarize.

The Docker way to upgrade containers seems to be the following:

Application containers should not store application data. This way you can replace app container with its newer version at any time by executing something like this:

You can store data either on host (in directory mounted as volume) or in special data-only container(s). Read more about it

Upgrading applications (eg. with yum/apt-get upgrade) within containers is considered to be an anti-pattern. Application containers are supposed to be immutable, which shall guarantee reproducible behavior. Some official application images (mysql:5.6 in particular) are not even designed to self-update (apt-get upgrade won’t work).

I’d like to thank everybody who gave their answers, so we could see all different approaches.

By not immediately removing the original my_mysql_container yet, you have the ability to revert back to the known working container if the upgraded container doesn’t have the right data, or fails a sanity test.

At this point, I’ll usually run whatever backup scripts I have for the container to give myself a safety net in case something goes wrong

Now you have the opportunity to make sure the data you expect to be in the new container is there and run a sanity check.

The docker volumes will stick around so long as any container is using them, so you can delete the original container safely. Once the original container is removed, the new container can assume the namesake of the original to make everything as pretty as it was to begin.

There are two major advantages to using this pattern for upgrading docker containers. Firstly, it eliminates the need to mount volumes to host directories by allowing volumes to be directly transferred to an upgraded containers. Secondly, you are never in a position where there isn’t a working docker container; so if the upgrade fails, you can easily revert to how it was working before by spinning up the original docker container again.

How To Update Docker Container to Latest Version

READING TIME: 4 MINUTES

In this guide, I’m going to show you how to update one of your docker containers to the latest version in just a few short steps.

You can follow this tutorial for any running container you have. The process is pretty simple: Check for the image repository name, download(pull) the new image, stop the running container, delete the old container, and then launch a new container with the updated image.

Let’s get started!

Step 1: Check Current Images

First, SSH into your docker host. Then, you need to check what your container image name is.

It should then show you a full list of pulled images. As you can see, the image I’d like to update is called b4bz/homer.

Step 2: Pull the new image

Then, pull the new image with this command. Replace the repository with whatever container you’d like to update.

By default, it will pull the latest version available. You can pull a specific version if you’d like, but for this example we want the latest.

Step 3: Stop & Remove Old Container

Before you can launch the new container, you first need to stop and remove the old container. If using bind mounts (which you should be doing), you won’t lose any data. It will just remove the old outdate image so you can load the Homer dashboard with the new version.

To stop and remove the old container, first you need to find the name of the running container.

Under the CONTAINER ID section, find the container ID of the image you want to update.

It does format the CONTAINER ID section a little weird and makes it a little hard to distinguish which ID goes to which container, so a neat trick I like to use is to highlight the entire row. I know my Homer dashboard runs on port 8092, so I can be sure I’m removing the correct container.

Stop the Running Container

Copy the container ID by using CTRL+SHIFT+C. (Regular CTRL+C to copy won’t work).

Then, type this command (to paste the container ID, use CTRL+SHIFT+V):

Remove the old container

Then, remove or delete the old container.

Step 4: Launch the new container

Launch New Container with a Docker-Compose file

Next, we are going to navigate to the directory where your Docker-compose.yml file is located for the container. Mine is located at /srv/config/Homer.

Then, create the new container.

Launch New Container with Docker Run

If you’re container was created using regular Docker run, then the command to launch the new container would look similar to this:

Wrapping Up

That’s it! Your image is now updated. If you had a previous version of container running, you may need to restart the container after creating it (not 100% sure if this is necessary). Make sure you are in the correct directory (ie. – /srv/config/Homer), and then run this:

Danny

Hey there! I’m Danny, owner and writer of Smart Home Pursuits. I’ve worked as an IT Manager for 8 years and enjoy using my knowledge to make my smart home «smarter».