Jenkins running in Docker Container but unable to launch it on browser - docker

I have docker installed on Google cloud and I have pulled the Jenkins image from Docker Hub to my docker. Now when I am running a container with Jenkins image using below mentioned command its showing "INFO: Jenkins is fully up and running". But when I tried it on a browser with "http://cloud_external_ip:port" it is not getting opened. It's throwing the message: "This site can’t be reached".
docker container run -p 80:80 --name myjen jenkins

have you tried to check your firewall-rules from the Cloud Shell, for example:
$gcloud compute firewall-rules list | grep 80
then if you need to setup new rule:
$gcloud compute firewall-rules create default-allow-http --allow tcp:80
for more info you can take a look at Google Doc

The Jenkins default port is 8080. You can find out all the ports mapped in your docker using:
$ docker ps -l
or only for one container:
$ docker port myappname
and in the results you need to search for Jenkins and ExposedPorts, and looks similar to this:
“ExposedPorts”: {
“8080/tcp”: {}
},
If you didn't change the default port for Jenkins and you was using this documentation during the installation it's possible that your Jenkins is working on 8080 port.
After check your ports if you want/need to change it in Jenkins you have two options:
by command: java -jar jenkins.war --httpPort=80
Modifying Jenkins config file: /PATH/jenkins, search for HTTP_PORT, and you add your selected port: HTTP_PORT = 80
You need to restart the service after modify the parameter.
If you want to use the port 8080 make sure that you have the correct firewall rules in GCP for this port. You can use the commands appointed by #J.Rojas.

If you're running a web app inside a docker container then before browsing it into the web browser you'll need to do PORT MAPPING.
Instead of running
docker run jenkins
Run this
docker run -p 8080:8080 jenkins
This will map your localhost to the internal IP of the container and you can access the application easily.
To change the port you can do:
docker run -p 8356:8080 jenkins
It can be accessed on port 8356.
Thanks

Related

Not able to run localhost:8000 for splunk in a docker container

I used the below command to start the splunk server using Docker.
docker run -d -e "SPLUNK_START_ARGS=--accept-license" -e "SPLUNK_USER=root" -p "8000:8000" splunk/splunk
But when I opened the URL localhost:8000, I am getting Server can't be reached message
What am I missing here?
I followed a tutorial from the source :- https://medium.com/#caysever/docker-splunk-logging-driver-c70dd78ad56a
Depending on your docker version and host OS, you could be missing the need to map 8080 from the VirtualBox.
This should not be needed if you are using HyperV (Windows host) or XHyve (Mac host), but can still be needed with VirtualBox.
The link to the Docker Image is https://hub.docker.com/r/splunk/splunk/. Referring to this we can see some details related to pulling and running the image. According to the link the right command is:
docker run -d -p 8000:8000 -e "SPLUNK_START_ARGS=--accept-license" -e "SPLUNK_PASSWORD=<password>" --name splunk splunk/splunk:latest
This works correctly for me. The image uses Ansible to do the configurations once the container has been created. If you do not specify password, the respective Ansible task will fail and your container will not be configured.
To follow the progress of the container configuration, you may run this command after running the above command:
docker logs -f splunk
Given that the name of your container is splunk. Here you will be able to see the progress of Ansible in configuring Splunk.
In case you are looking to create a clustered Splunk deployment then, you might want to have a look at this: https://github.com/splunk/docker-splunk
Hope this helps!

How to identify the docker host ip to use when running a jenkins container

I have docker machine installed on windows OS and have pulled in Jenkins image from docker hub. I then run the below commands:
docker volume created myjenkins-data
docker run -p 8080:8080 -p 50000:50000 -v myjenkins-data:/var/jenkins_home jenkins
I received the admin key for Jenkins in the logs. I've confirmed that my container is still running status:
$ docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
2854c7d83879 jenkins "/bin/tini -- /usr..." About a minute ago Up About a minute 0.0.0.0:8080->8080/tcp, 0.0.0.0:50000->50000/tcp quizzical_cray
Now, I need to log into 8080 port to view the Jenkins web app. But I do not know which host ip to use. I identified the docker host ip with the command "docker-machine ip" and got the ip address: 192.168.99.100. But using 192.168.99.100:8080 did not bring up Jenkins app. I also tried using docker inspect to get the container's ip, but port 8080 didn't work on those ips as well. Which ip address do i use to see the Jenkins app that is running in the container?
First, double-check if http://localhost:8080 is not enough.
Hyper-V (through vpnkit, if you are using Docker for Windows) should have done the port-forwarding for you.
If you are using the legacy docker toolbox (VirtualBox), then you need port-forwarding (issue 4115).

Build/push image from jenkins running in docker

I have two docker containers - one running jenkins and one running docker registry. I want to build/push images from jenkins to docker registry. How do I achieve this in an easy and secure way (meaning no hacks)?
The easiest would be to make sure the jenkins container and registry container are on the same host. Then you can mount the docker socket onto the jenkins container and use the dockerd from the host machine to push the image to the registry. /var/run/docker.sock is the unix socket the dockerd is listening to.
By mounting the docker socket any docker command you run from that container executes as if it was the host.
$ docker run -dti --name jenkins -v /var/run/docker.sock:/var/run/docker.sock jenkins:latest
If you use pipelines, you can install this Docker Plugin https://plugins.jenkins.io/docker-workflow,
create a credentials resource on Jenkins,to access the Docker registry, and do this in your pipeline:
stage("Build Docker image") {
steps {
script {
docker_image = docker.build("myregistry/mynode:latest")
}
}
}
stage("Push images") {
steps {
script {
withDockerRegistry(credentialsId: 'registrycredentials', url: "https://myregistry") {
docker_image.push("latest")
}
}
}
}
Full example at: https://pillsfromtheweb.blogspot.com/2020/06/build-and-push-docker-images-with.html
I use this type of workflow in a Jenkins docker container, and the good news is that it doesn't require any hackery to accomplish. Some people use "docker in docker" to accomplish this, but I can't help you if that is the route you want to go as I don't have experience doing that. What I will outline here is how to use the existing docker service (the one that is running the jenkins container) to do the builds.
I will make some assumptions since you didn't specify what your setup looks like:
you are running both containers on the same host
you are not using docker-compose
you are not running docker swarm (or swarm mode)
you are using docker on Linux
This can easily be modified if any of the above conditions are not true, but I needed a baseline to start with.
You will need the following:
access from the Jenkins container to docker running on the host
access from the Jenkins container to the registry container
Prerequisites/Setup
Setting that up is pretty straight forward. In the case of getting Jenkins access to the running docker service on the host, you can do it one of two ways. 1) over TCP and 2) via the docker unix socket. If you already have docker listening on TCP you would simply take note of the host's IP address and the default docker TCP port number (2375 or 2376 depending on whether or not you use TLS) along with and TLS configuration you may have.
If you prefer not to enable the docker TCP service it's slightly more involved, but you can use the UNIX socket at /var/run/docker.sock. This requires you to bind mount the socket to the Jenkins container. You do this by adding the following to your run command when you run jenkins:
-v /var/run/docker.sock:/var/run/docker.sock
You will also need to create a jenkins user on the host system with the same UID as the jenkins user in the container and then add that user to the docker group.
Jenkins
You'll now need a Docker build/publish plugin like the CloudBees Docker Build and Publish plugin or some other plugin depending on your needs. You'll want to note the following configuration items:
Docker URI/URL will be something like tcp://<HOST_IP>:2375 or unix:///var/run/docker.sock depending on how we did the above setup. If you use TCP and TLS for the docker service you will need to upload the TLS client certificates for your Jenkins instance as "Docker Host Certificate Authentication" to your usual credentials section in Jenkins.
Docker Registry URL will be the URL to the registry container, NOT localhost. It might be something like http://<HOST_IP>:32768 or similar depending on your configuration. You could also link the containers, but that doesn't easily scale if you move the containers to separate hosts later. You'll also want to add the credentials for logging in to your registry as a username/password pair in the appropriate credentials section.
I've done this exact setup so I'll give you a "tl;dr" version of it as getting into depth here is way outside of the scope of something for StackOVerflow:
Install PID1 handler files in container (i.e. tini). You need this to handle signaling and process reaping. This will be your entrypoint.
Install some process control service (i.e. supervisord) packages. Generally running multiple services in containers is not recommended but in this particular case, your options are very limited.
Install Java/Jenkins package or base your image from their DockerHub image.
Add a dind (Docker-in-Docker) wrapper script. This is the one I based my config on.
Create the configuration for the process control service to start Jenkins (as jenkins user) and the dind wrapper (as root).
Add jenkins user to docker group in Dockerfile
Run docker container with --privileged flag (DinD requires it).
You're done!
Thanks for your input! I came up with this after some experimentation.
docker run -d \
-p 8080:8080 \
-p 50000:50000 \
--name jenkins \
-v pwd/data/jenkins:/var/jenkins_home \
-v /Users/.../.docker/machine/machines/docker:/Users/.../.docker/machine/machines/docker \
-e DOCKER_TLS_VERIFY="1" \
-e DOCKER_HOST="tcp://192.168.99.100:2376" \
-e DOCKER_CERT_PATH="/Users/.../.docker/machine/machines/docker" \
-e DOCKER_MACHINE_NAME="docker" \
johannesw/jenkins-docker-cli

how does env.BUILD_URL in jenkins running inside Docker container get the outside network port number correctly?

Trying out jenkins from official docker image of jenkins
docker run -d -p 8090:8080 jenkins
Note that I have chosen my host's 8090 port to map to the docker container's 8080 port.
Now, inside jenkins, i am running a sample pipeline where I have only one line
echo "${env.BUILD_URL}"
As a result of this pipeline script, the pipeline console output shows the following
http://localhost:8090/job/sample_pipeline/1/
Notice the port number 8090?
My question is,
How does jenkins from inside the container know that i have set 8090 as the host port that should map to the jenkins container's 8080 port?
I mean, with env.BUILD_URL being invoked from inside the docker container, isn't jenkins supposed to look into its own host and return port 8080 as the port number where it is running?
Jenkins is not supposed to know that it's running as a container and that it needs to look outside its container scope to determine what is the external port number that it is mapped to?
Since you are using http://localhost:8090 to access the console and trigger the build I would guess that it picks it up from there.

Obtaining the ip address of a docker container

I have a ubuntu machine which is a VM where I have installed docker in it. I am using this machine from my local windows machine and doing ssh , opening the terminal to the ubuntu machine.
Now , I am going to take a docker image which contains all the necessary softwares for eg: apache installed in it. Later I am going to deploy a sample appication(which is a web applicationP on to it and save it .
Now , I am in a confused mode as in how to check the deployed application if its running properly. i.e., what would be the address of the container which containds the deployed application.
for eg:- If I type http://127.x.x.x which is the address of the ubuntu machine , I am just getting time out .
Can anyone tell me how to verify the deployed application . Also, the printing the output of the program on the console works seemlessly fine , as the output gets printed , only thing I have some doubts is regarding the web application.
There are some possibilities to check whether your app is running.
Remote API
As JimiDini said, one possibility is the Docker remote API. You can use it to see all running containers (which would be your use case, right?), inspect a certain container or start and stop containers. The API is a REST-API with several binding for programming languages (at https://docs.docker.io/reference/api/remote_api_client_libraries/). Some of them are very outdated. To use the Docker remote API from another machine, I needed to open it explicitly:
docker -H tcp://0.0.0.0:4243 -H unix:///var/run/docker.sock -d &
Note that the API is open to the world now! In a real scenario you would need to secure it in some way (e.g. see the example at http://java.dzone.com/articles/securing-docker%E2%80%99s-remote-api).
Docker PS
To see all running containers run docker ps on your host. This will list all running containers. If you do not see your app, it is not running. It also shows you the ports your app is exposing. You can also do this via the remote API.
Logs
You can also check the logs. You can run docker attach <container id> to attach to a certain container an see its stdout. You can run also run docker logs <container id> to receive the Docker logs. What I prefer is to write the logs to a certain directory, e.g. all logs to /var/log and mount this folder to my host machine. Then all your logs will end up in /home/ubuntu/docker-logs on your host.
docker run -p 80:8080 -v /home/ubuntu/docker-logs:/var/log:rw my/application
One word to ports and IP
Every container will get its own IP address. You can check this IP address via the remote API or via Docker on the host machine directly. You can also specify a certain host name for the container (by passing the --hostname="test42" to the run command). However, you mostly did not need that.
To access the application in the container, you need to open the port in the container and bind to a port on the host.
In your Dockerfile you need to EXPOSE the port your app runs on:
FROM ubuntu
...
EXPOSE 8080
CMD run-my-app.sh
When you start your container, you need to bind this port to a port of the host:
docker run -p 80:8080 my/application
Now you can access your app on http://localhost:80 or http://127.0.0.1:80.
If you app does not response, check if the container is running by typing docker ps or the remote API. If it is not running, check the logs for the reason.
(Note: If you run your Ubuntu VM in something like VirtualBox and you try to access it from your Windows machine, make sure you opened the ports in VirtualBox too!).
Docker container has a separate IP address. By default it is private (accessible only from the host-machine).
Docker provides all metadata (including IP address) via its API:
https://docs.docker.io/reference/api/docker_remote_api_v1.10/#inspect-a-container
https://docs.docker.io/reference/api/docker_remote_api_v1.10/#monitor-docker-s-events
You can also take a look at a little tool called docker-gen for inspiration. It monitors docker-events and created configuration-files on host machine using templates.
To obtain the ip address of a docker container, if you know its id (a long hex string) or if you named it:
docker inspect --format '{{ .NetworkSettings.IPAddress }}' <container-id-or-name>
Docker is running its own network and to get information about it you can run the following commands:
docker network ls
docker network inspect <network name>
docker inspect <container id>
In the output, you should be able to find the IP.
But there is also a couple of things you need to be aware of, regarding Dockerfile and docker run command:
when you EXPOSE a port in Dockerfile, the service in the container is not accessible from outside Docker, but from inside other Docker containers
and when you EXPOSE and use docker run -p ... flag, the service in the container is accessible from anywhere, even outside Docker
So for example, if your apache is running on port 8080 you should expose it in Dockerfile and then you can run it as:
docker run -d -p 8080:8080 <image name> and you should be able to access it from your host on HTTP://localhost:8080.
It is an old question/answer but it might help somebody else ;)
working as of 2020
docker inspect -f '{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' container_name_or_id

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