remote Docker Repository behaviour in Artifactory - docker

I have a remote docker repository configured in Artifactory (to docker hub). To test it I've created docker image A and pushed it to docker hub.
The image is user-name/image:latest.
Now I can pull it from artifactory using artifactory-url/docker/user-name/image:latest.
Now I've updated image A to image B and pushed it to docker hub. When I remove my local images and pull this image again from Artifactory I still get the image A (so it seems the cache is used). When I set the following setting to zero (Metadata Retrieval Cache Period) I'll pull the updated image B.
All fine. Now I increase the Metadata Retrieval Cache Period setting again. I've now deleted the image from docker hub and try to pull it again using artifactory. This fails while I was hoping it would just pull the image from the Artifactory cache?
I can also not pull it using the cache directly: docker pull artifactory-url/docker-cache/user-name/image:latest.
Is there a way to use a docker image from artifactory which is deleted in the remote repository?

The first part you wrote is ok and its the expected behavior. Now, for the second part, it's also the expected behavior and I will explain why - when you use a virtual repository as your Artifactory Docker registry, it will always search for artifacts in the local repositories first, then in the remote-cache, and only then in the remote itself. However, if Artifactory finds the package in the local or remote-cache repositories, it will always also check the remote for newer versions. This causes cached images that are deleted from the remote itself to not be downloadable from the remote-cache in Artifactory, since Artifactory receives a 404 error from the remote repository. You can fix this by moving the image to the local repository, and you will be able to pull it.

Related

The push refers to repository [docker.io/chatapp/monorepo] An image does not exist locally with the tag: chatapp/monorepo

I'm trying to push a Bitbucket repository to a private repository in Docker Hub as Docker image file. The build is successful to the point until I get this error:
docker push chatapp/monorepo
+ docker push chatapp/monorepo
The push refers to repository [docker.io/chatapp/monorepo]
An image does not exist locally with the tag: chatapp/monorepo
Does this have anything to do with how the Dockerfile inside the Bitbucket repository is written? Or are there some scripts missing in bitbucket-pipeline.yml file?
I'm new to Docker and I can't seem to figure this out.
The error signifies that the image you're trying to push doesn't exist locally on the machine you're trying to push from. Run docker images and check if it's there, if not there's a problem with the pipeline creating it, if it does but with a different name try and fix that.

Automatically pull docker image container

I have a linux bare-metal server with docker installed.
I work on an asp.net core project on my computer.
My source code is pushed on github.
Each time i commit and push something, github triggers a webhook on my docker hub account.
Docker hub builds me a new image which contains my asp.net core application binaries. (docker hub also run the tests)
This image works fine when i pull it manually on my server.
My question is how can i do this automatically ? Is there a way for my server to "detect" that docker hub contains a new version of the image and run something to pull this image and fire database migrations automatically ?
Thanks
If you have a public ip which external internet such as dockerhub could visit you, then you can use Docker Hub Webhooks:
You can create webhooks like next diagram, set the url which external could visit your service, when image was pushed, it will post some json data to the url you afforded, one example data here, then your own url could receive data and do related things as you like.
And, if you use jenkins, there are lots of plugin help you to do similar things: refer Triggering Docker pipelines with Jenkins, also Polling Docker Registries for Image Changes
If you not have a public ip which dockerhub could visit, then I guess you had to poll dockerhub to see if new image there...

How do you cache images pulled from docker hub into the private docker registry?

The first line of my .gitab-ci.yml is the following:
image: gradle:5.0-jdk11
This image is 601mb and I am constantly having to pull it from docker hub on every invocation of my build.
Is there any way that the image can be stored on the project's docker repository in Gitlab? So that it is automatically placed there the first time the build is run and then retrieved from there on subsequent invocations of the build?
If your Gitlab-runner already pulled the Docker-image, next time it needs it, it will pull the local image instead of downloading again the 601mB image. This is the default behaviour unless ou change as in https://docs.gitlab.com/runner/executors/docker.html#how-pull-policies-work
Keep in mind that f the image is removed from your gitlab-runner local images, it will have to pull it from scratch.
That should be described by the page "Cache dependencies in GitLab CI/CD ", declaring your image as an artifact in the cache (defined by cache:paths)
It’s sometimes confusing because the name artifact sounds like something that is only useful outside of the job, like for downloading a final image.
But artifacts are also available in between stages within a pipeline.
So if you build your application by downloading all the required modules, you might want to declare them as artifacts so that each subsequent stage can depend on them being there
Check also what your Docker runner cache directory includes.
If the issue persists, try and use a private registry, as in issue 41924:
image: my-private-registry:5000/my-ci-image:latest

Docker trigger jenkins job when image is pushed

I am trying to build a jenkins job(trigger builds remotely) on docker image build, build all I am getting on docker hub is following:
HISTORY
ID Status Date & Time
7345... ! ERROR 10/12/17 10:03
Reason (I assume): Docker is not authenticated to post to the jenkins url.
Question: How can I trigger the job automatically when an image gets pushed to docker hub?
Pull and run Watchtower docker image to poll any third-party public Docker image on Docker Hub or Quay that you need (typically as a base image of your own containers). Here's how. "Polling" here does not imply crudely pulling the whole image every 5 minutes or so - we are monitoring periodically for changes in the image, downloading only the checksum (SHA digest) most of the time (when there are no changes in the locally cached image).
Install the Build Token Root Plugin in your Jenkins server and set it up to receive Slack-formatted notifications secured with a token to trigger builds remotely or - safer - locally (those triggers will be coming from Watchtower container, not Slack). Here's how.
Set up Watchtower to post Slack messages to your Jenkins endpoint upon every change in the image(s) (tags) that you want. Here's how.
Optionally, if your scale is so large that you could end up overloading and bringing down the entire Docker Hub with a flood HTTP GET requests (should the time triggers go wrong and turn into a tight loop) make sure to build in some safety checks on top of Watchtower to "watch the watchman".
You can try the following plugin: https://wiki.jenkins.io/display/JENKINS/CloudBees+Docker+Hub+Notification
Which claims to do what you're looking for.
You can configure a WebHook in DockerHub wich will trigger the Jenkins-Build.
Docker Hub webhooks targeting your Jenkings server endpoint require making periodic copies of the image to another repo that you own [see my other answer with Docker Hub -> Watchman -> Jenkins integration through Slack notifications].
More details
You need to set up a cron job with periodic polling (docker pull) of the source repo to [docker] pull its `latest' tag, and if a change is detected, re-tag it as your own and [docker] push to a repo you own (e.g. a "clone" of the source Docker Hub repo) where you have set up a webhook targeting your Jenkings build endpoint.
Then and only then (in a repo you own) will Jenkins plugins such as Docker Hub Notification Trigger work for you.
Polling for Dockerfile / release changes
As a substitute of polling the registry for image changes (which need not generate much network traffic thanks to the local cache of docker images) you can also poll the source Dockerfile on Github using wget. For instance Dockerfiles of the official Docker Hub images are here. In case when the Github repo makes releases, you can get push notifications of them using Github Watch > Releases Only feature and if they have CI docker builds. Docker images will usually be available with a delay after code releases, even with complete automation, so image polling is more reliable.
Other projects
There was also a proposal for a 2019 Google Summer of Code project called Polling Docker Registries for Image Changes that tried to solve this problem for Jenkins users (incl. apparently Google), but sadly it was not taken up by participants.
Run a cron job with a periodic docker search to list all tags in the docker image of interest (here's the script). Note that this script requires the substitution of the jannis/jq image with an existing image (e.g. docker run --rm -i imega/jq).
Save resulting tags list to a file, and monitor it for changes (e.g. with inotifywait).
Fire a POST request using curl to your Jenkins server's endpoint using Generic Webhook Trigger plugin.
Cautions:
for efficiency reasons this tags listing script should be limited to a few (say, 3) top pages or simple repos with a few tags,
image tag monitoring relies on tags being updated correctly (automatically) after each image change, rather than being stuck in the past, like say Ubuntu tags (e.g. trusty-20190515 was updated a few days ago - late November, without the change in its mid-May tag).

Docker: updating image and registry

What is the right workflow for updating and storing images?
For example:
I download source code from GitHub (project with Docker files, docker-compose.yml)
I run "docker build"
And I push new image to Docker Hub (or AWS ECR)
I make some changes in source code
Push changes to GitHub
And what I should do now to update registry (Docker Hub)?
A) Should I run again "docker build" and then push new image (with new tag) to registry?
B) Should I somehow commit changes to existing image and update existing image on Docker Hub?
This will depend on what for you will use your docker image and what "releasing" policy you adopt.
My recommendation is that you sync the tags you keep on Docker Hub with the release/or tags you have in GitHub and automate as much as you can your production with a continuous integration tools like Jenkins and GitHub webooks.
Then your flow becomes :
You do your code modifications and integrate them in GitHub ideally using a pull request scheme. This means your codes will be merged into your master branch.
Your Jenkins is configured so that when master is changed it will build against your docker file and push it to Docker hub. This will erase your "latest" tag and make sure your latest tag in docker hub is always in sync with your master release on GitHub
If you need to keep additional tags, this will be typical because of different branches or releases of your software. You'll do the same as above with the tag hooked up through Jenkins and GitHub webhooks with a non-master branch. For this, take a look at how the official libraries are organized on GitHub (for example on Postgres or MySQL images).

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