I am learning docker, just getting my feet wet... I begin begging your pardon since I will probably using terminology badly :-(
I have successfully built my first container and run it locally.
The container image is a node.js + express web app.
Locally I run my image this way:
docker run -p 80:3000 myname/myimage
If I point my browser to the local server IP
http://192.168.1.123:80/
I access my app in all of its glory.
Then, I push it to docker hub with this command:
docker push myname/myimage
So far so good. The question is: am I supposed to be able to run my app from docker cloud, already, or should I push it to AWS, for example?
By executing docker push myname/myimage you only sent your image to docker-hub.
This image can then be run to create a container; but as is, it is not running.
You effectively will have to run it on any machine or service in order to access your app.
concerning the terminology:
you build an image, not a container
you push (or pull) an image to (from) docker-hub
you run a container from an image
Related
I want to implement CI/CD for my application, so far I have managed to build and upload my image on docker hub with GitHub actions. Now I need a way to pull that image on my VPS and run the docker image. I do not know how to achieve that, I tried multiple youtube videos but none show that.
Could someone point me to the right direction?
What I have done is:
Setup a webhook on vps, this serves as a webhook server, define a endpoint and a script to redeploy (Will be executed when endpoint is called and met)
In your GitHub ctions flow, add new a step, send a request to this webhook server endpoint
Usually flow after image exists in Dockerhub is:
you use the docker login command to log in to the user which has permissions to pull the image
You can either pre pull the image using the docker pull command or you can straight on just use the docker run command and it will pull the image if not existing and run it.
For an example with Nginx, the image resides in Dockerhub and with help of official docs you can see
docker run --name mynginx1 -p 80:80 -d nginx
the command which will pull the Nginx image (latest in this case) and run the container with the name of mynigninx1 and expose the port on host 80 and map it to port 80 inside the container.
There is a docker image you can run on your server to watch your working or selected docker containers and when there is a new push to the docker hub registry then it will update your docker image of your project
Its called watchtower
containrrr/watchtower
Newer to Docker and trying to understand how images work. I ran the following command:
sudo docker search hello-world
and it returned this:
docker.io docker.io/carinamarina/hello-world-app This is a sample Python web application,
I then ran:
sudo docker run docker.io/carinamarina/hello-world-app
...and this was the output from the terminal:
* Running on http://0.0.0.0:5000/ (Press CTRL+C to quit)
I don't understand. How can the IP address be 0.0.0.0? I entered that into a browser and got nothing. I tried localhost:5000 and got nothing.
How does one get to see this webapp run?
tl;dr
you need to publish the port to the host network to see the application working
long version:
well good for you to start working with docker
I will start with explaining a little bit about docker then I will explain what is happing over there
First of all, there is a difference between "image" and "container"
Image is the blueprint that is used to create containers from
so you write the definition of the image like (install this, copy that from the host or build that.......etc) in the image file and then you tell docker to build this image and then RUN containers from that image
so if you have like 1 image and you run 2 containers from it they both will have the same instructions( definition )
what happened with you
when you invoke the RUN command first thing you will see is
Unable to find image 'carinamarina/hello-world-app:latest' locally
That's mean that the local docker will not find the image(blueprint) locally with the name docker.io/carinamarina/hello-world-app so it will do the following steps
so it will start pulling the image from the remote registry
then
then it will start extracting the layers of the image
then it will start the container and show the logs from INSIDE CONTAINER
Why it didn't run with you
the application is running inside the container on port 5000
the container has a whole different network than the host that's running on (centos7 machine in your case )
you will have to make a port forwarding between the docker network and the host network so you can USE the application from the HOST
you can read more about that here docker networking
I recommend the following places to start with
let's play with docker
docker tutorial for beggines
Hi i have problem with updating / changing image of my service on the server running Docker swarm mode.
Here is the process of manually updating the service.
push the project to gitlab from local machine.
pull the project from gitlab in server.
build a Docker image as my-project:latest
tag my-project:latest as registry.gitlab.com/my-group/my-project:staging
i push the image using docker push registry.gitlab.com/my-group/my-project:staging
i run docker stack deploy -c ~/docker-stack.yml api --with-registry-auth
and it works fine.
However if i move the codes above into a gitlab-ci.yml despite of ending the job successfully i get an error when it is trying to update the service.
Updating service api_backend (id: r4gqmil66kehzf0oehzqk57on)
image registry.gitlab.com/my-group/my-project:staging could not be accessed on a registry to record
its digest. Each node will access registry.gitlab.com/my-group/my-project:staging independently,
possibly leading to different nodes running different
versions of the image.
Also the gitlab runner is executing commands in Shell mode.
I have tried different solutions as you can see i'm even using the --with-registry-auth flag.
To summarize this:
everything works fine if i enter the codes manually but i get an error when i use gitlab-ci.yml.
I'm new to docker.Most of the tutorials on docker cover the same thing.I'm afraid I'm just ending up with piles of questions,and no answers really. I've come here after my fair share of Googling, kindly help me out with these basic questions.
When we install a docker,where it gets installed? Is it in our computer in local or does it happen in cloud?
Where does containers get pulled into?I there a way I can see what is inside the container?(I'm using Ubuntu 18.04)
When we pull an image.Docker image or clone a repository from
Git.where does this data get is stored?
Looks like you are confused after reading to many documents. Let me try to put this in simple words. Hope this will help.
When we install a docker,where it gets installed? Is it in our
computer in local or does it happen in cloud?
We install the docker on VM be it you on-prem VM or cloud. You can install the docker on your laptop as well.
Where does containers get pulled into?I there a way I can see what is
inside the container?(I'm using Ubuntu 18.04)
This question can be treated as lack of terminology awareness. We don't pull the container. We pull the image and run the container using that.
Quick terminology summary
Container-> Containers allow you to easily package an application's code, configurations, and dependencies into a template called an image.
Dockerfile-> Here you mention your commands or infrastructure blueprint.
Image -> Image gets derived from Dockerfile. You use image to create and run the container.
Yes, you can log inside the container. Use below command
docker exec -it <container-id> /bin/bash
When we pull an image.Docker image or clone a repository from
Git.where does this data get is stored?
You can pull the opensource image from Docker-hub
When you clone the git project which is docerized, you can look for Dockerfile in that project and create the your own image by build it.
docker build -t <youimagenae:tag> .
When you build or pull the image it get store in to your local.
user docker images command
Refer the below cheat-sheet for more commands to play with docker.
The docker daemon gets installed on your local machine and everything you do with the docker cli gets executed on your local machine and containers.
(not sure about the 1st part of your question). You can easily access your docker containers by docker exec -it <container name> /bin/bash for that you will need to have the container running. Check running containers with docker ps
(again I do not entirely understand your question) The images that you pull get stored on your local machine as well. You can see all the images present on your machine with docker images
Let me know if it was helpful and if you need any futher information.
A colleague find out Docker and want to use it for our project. I start to use Docker for test. After reading an article about Docker swarm I want to test it.
I have installed 3 VM (ubuntu server 14.04) with docker and swarm. I followed some How To ( http://blog.remmelt.com/2014/12/07/docker-swarm-setup/ and http://devopscube.com/docker-tutorial-getting-started-with-docker-swarm/). My cluster work. I can launch for exemple a basic apache container (the image was pull in the Docker hub) but I want to use my own image (an apache server with my web site).
I tested to load an image (after save it in a .tar) but this option isn't supported by the clustering mode, same thing with the import option.
So my question is : Can I use my own image without to push it in the Docker hub and how I do this ?
If your own image is based on a Dockerfile that you build you can execute the build command on your project while targeting the swarm.
However if the image wasn't built, but created manually you need to have a registry in between that you can push to, either docker hub or some other registry solution like https://github.com/docker/docker-registry