I have developed an application and am using docker to build it. I would like to ship it as a VMware OVF package. What are my options? How do I ship it so customer can deploy it in their VMware environment?
Also I am using a base Ubuntu image and installed NodeJS, MongoDB and other dependencies on it. But I would like to configure my NodeJS based application and MongoDB database as a service within the package I intend to ship. I know how to configure these as a service using init.d on a normal VM. How do I go about this in Docker? Should I have my init.d files in my application folder and copy them over to Docker container during build? Or are there better ways?
Appreciate any advise.
Update:
The reason I ask this question is - My target users need not know docker necessarily. The application should be easy to deploy for someone who do not have docker experience. With all services in a single VM makes it easy to troubleshoot issues. As in, all log files will be saved in the /var/log directory for different services and we can see status of all different services at once. Rather than the user having to look into each docker service. And probably troubleshooting issue with docker itself.
But at the same time I feel it convenient to build the application the docker way.
VMware vApps usually made of multiple VMs running to provide a service. They may have start up dependencies and etc.
Now Using docker you can have those VMs as containers running on a single docker host VM. So a single VM removes the need for vAPP.
On the other hand containerizing philosophy requires us to use Microservices. short explanation in your case, putting each service in a separate container. Then write up a docker compose file to bring the containers up and put it in start up. After that you can make an OVF of your docker host VM and ship it.
A better way in my opinion is to create docker images, put them in your repository and let the customers pull them. Then provide docker compose file for them.
Related
I am newbie with docker, i need some clarification here i am trying to explain
lets say i have Windows Machine and docker desktop installed on it.
what will be the structure may i need to first run Some Linux Distro Container and within that container i will install LAMP Server? or i will parallel create Apache Container MySQL Container and Linux Container?
Secondly i noticed that there are some wordpress containers which is totally confusing because to run wordpress defiantly i need LAMP, then how this architecture will work?
Will it be like:
1 Linux Container and then i will install LAMP on it and install wordpress?
But incase of this what will be the purpose of wordpress container?
Or
1 Linux Container
1 Apache Container
1 MySQL Container
1 Wordpress Container
and all of them will be interlinked??
i am too confused please help me
In general you will try to have 1 container = 1 service/ 1 purpose and keep the containers very small.
That means you will have your MySQL in one container and your Apache Server on another container. They will run on container-linux based (here you can go and read about docker and its layering technique).
Coming back to your architecture, you need to put the Wordpress somewhere, where a server is - because without a server the software has no power to do anything, that means you will put it on the Apache container, eventually you will want to volume (check docker docs) to persist your statical data.
Lastly, you will want to connect this container with the MySQL container to be able to persist the important data there. You can do that with docker-compose (see docs) and start both containers from one command.
Now the cool part: this is already done for you here bitnami/wordpress and I am sure you can find a lot more on docker hub.
I have to deploy my application software which is a linux based package (.bin) file on a VM instance. As per system requirements, it needs minimum 8vCPUs and 32GB RAM.
Now, i was wondering if it is possible to deploy this software over multiple containers that load share the CPU and RAM power in the kubernetes cluster, rather than installing the software on a single VM instance.
is it possible?
Yes, it's possible to achieve that.
You can start using docker compose to build your customs docker images and then build your applications quickly.
First, I'll show you my GitHub docker-compose repo, you can inspect the folders, they are separated by applications or servers, so, one docker-compose.yml build the app, only you must run a command docker-compose up -d
if you need to create a custom image with docker you should use this docker command docker build -t <user_docker>/<image_name> <path_of_files>
<user_docker> = your docker user
<image_name> = the image name that you choose
<path_of_files> = somelocal path, if you need to build in the same folder you should use . (dot)
So, after that, you can upload this image to Dockerhub using the following commands.
You must login with your credentials
docker login
You can check your images using the following command
docker images
Upload the image to DockerHub registry
docker push <user_docker>/<image_name>
Once the image was uploaded, you can use it in different projects, make sure to make the image lightweight and usefully
Second, I'll show a similar repo but this one has a k8s configuration into the folder called k8s. This configuration was made for Google cloud but I think you can analyze it and learn how you can start in your new project.
The Nginx service was replaced by ingress service ingress-service.yml and https certificate was added certificate.yml and issuer.yml files
If you need dockerize dbs, make sure the db is lightweight, you need to make a persistent volume using PersistentVolumeClaim (database-persistent-volume-claim.yml file) or if you use larger data onit you must use a dedicated db server or some db service in the cloud.
I hope this information will be useful to you.
There are two ways to achieve what you want to do. The first one is to write a dockerfile and create the image. More information about how to write a dockerfile can be found from here. Apart for that you can create a container from a base image and install all the software and packages and export it as a image. Then you can upload to a docker image repo like Docker Registry and Amazon ECR
I currently use Ansible to manage and deploy a fleet of servers.
I wish to start using Docker for some applications and would like to build a Docker image using the same scripts we use to configure on non Dockerized hosts.
For example we have an Ansible role that builds Nginx with 3rd party modules, would like to use the same role to build a Docker image with the custom Nginx.
Any ideas how I would get this done?
There is the "Ansible Container" project, https://www.ansible.com/integrations/containers/ansible-container. That page points also to the github repo.
It is not clear how well maintained it is, but their reasoning and approach makes sense.
Consider that you might have some adjustments to do regarding two aspects:
a container should do only one thing (microservice)
how to pass configuration to the container at runtime (Docker has some guidelines, such as environmental variables if possible or mounting a volume with the configuration files)
That's a perfect example where the docker-systemctl-replacement script should be used.
It has been developed to allow ansible scripts to target both virtual machines and docker containers. It had been developed when distros did switch to systemd which was hard to enable for containers. When overwriting /usr/bin/systemctl then the docker container will then look good enough for ansible that all the old scripts will continue to run, installing rpm/deb, and having 'service:'s started and enabled.
I am going to work with Node.js and PostgreSQL on Linux. I read many hours about how docker actually works. Still I am not sure that is docker environment needed before starting my project or I can use docker after completion of the project?
Lets first understand what docker is and how you can use it in your project.
Docker have three core concepts:
1) Docker engine : a lightweight runtime and robust tooling that builds and runs your Docker containers.
2) Docker image : a carbon copy of your project environment including all environment dependencies like base operating system, host entries, environment variables, databases, web/application servers. In your case, Linux distribution of your choice, node.js and required modules, PostreSQL and it's configuration.
3) docker container : can be visualized as an virtual Linux server running your project. Each time you use docker run, a new container is launched from the docker image.
You can visualize a docker-environment as an lightweight virtual machine where you can run your project without any external interference(host entries/environment variables/ RAM/ CPU) from other projects.
So as a developer, you can develop your project on your Dev machine and once it's ready to be pushed to QA/Staging you can build a docker image of your project which then can be deployed on any environment(QA/Staging/Production).
You can launch multiple container from your image on single or multiple physical servers.
You can introduce Docker whenever you want. If using multiple servers then you can create a Docker container with one server in it and the other (non-Dockerised solution) makes requests to that.
Or you could Dockerise them both.
Basically, introduce Docker when you feel the time is right.
I like to divide a large project into multiple sections - e.g. front end web sever, backend authentication server, backend API server 1, backend API server 2, etc.
As each part of the project gets completed, I Dockerise it. The other parts then use the Dockerised solution.
I'm planning to set up a jenkins-based CD workflow with Docker at the end.
My idea is to automatically build (by Jenkins) a docker image for every green build, then deploy that image either by jenkins or by 'hand' (I'm not yet sure whether I want to automatically run each green build).
Getting to the point of having a new image built is easy. My question is about the deployment itself. What's the best practice to 'reload' or 'restart' a running docker container? Suppose the image changed for the container, how do I gracefully reload it while having a service running inside? Do I need to do the traditional dance with multiple running containers and load balancing or is there a 'dockery' way?
Suppose the image changed for the container, how do I gracefully reload it while having a service running inside?
You don't want this.
Docker is a simple system for managing apps and their dependencies. It's simple and robust because ALL dependencies of an application are bundled with it. If your app runs today on your laptop, it will run tomorrow on your server. This is because we have captured 100% of the "inputs" for your application.
As soon as you introduce concepts like "upgrade" and "restart", your application can (accidentally) store state internally. That means it might behave differently tomorrow than it does today (after being restarted and upgraded 100 times).
It's better use a load balancer (or similar) to transition between your versions than to try and muck with the philosophy of Docker.
The Docker machine itself should always be immutable as you have to replace it for a new deployment. Storing state inside the Docker container will not work when you want to ship new releases often that you've built on your CI.
Docker supports Volumes which will let you write files that are permanent into some folder on the host. When you then upgrade the Docker container you use the same volume so you've got access to the same files written by the old container:
https://docs.docker.com/userguide/dockervolumes/