Can you have multiple containers in Codenvy, like a server container and a mysql container?
Or is Codennvy an enriched container itself - just embeddet with different frameworks installed incl. ide?
You can have multiple containers - any you want as defined in a Docker Compose file. If you sign up for an account and create a workspace with the "Java-MySQL" stack you'll get a sample app using an app server and database.
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I have installed and configured a system in EC2s using Ansible. It is 1 EC2 master with a few EC2 workers. Sometimes when I use ansible to update or reinstall configuration, it fails because either some package has been removed from open-source repositories, or the package is updated so not compatible with some other packages. And I learned that using docker-container can resolve these kind of configuration problems.
However, according to what I learned, each docker image will create image of one application (I guess one application means one process). But mine is a system which has airflow master webserver, airflow worker webserver, flower webserver, rabbitmq, airflow celery, several configuration files, etc. how can I create docker images for that? Should I create one docker image for each process? How do I know which linux folder should I go to create each docker image? How do I know which applications/processes I need to create? And how to combine these images to make them work together as a system?
Or maybe in my case I should not use docker image, Instead I should just create an EC2 image?
Use docker-compose.
Compose is a tool for defining and running multi-container Docker applications
https://docs.docker.com/compose/
each docker image will create image of one application (I guess one application means one process)
That is basically correct. You should create one docker-container per application. In theory you can have multiple process per container, but that doesn't matter in this case.
how can I create docker images for that?
In your case you should make one docker-container for airflow master webserver, one for airflow worker webserver, one for flower webserver, etc. And the you use a docker-compose.yml to link them all together.
Should I create one docker image for each process?
generally yes. (It may depend on your exact setup though)
And how to combine these images to make them work together as a system?
docker-compose.
How do I know which linux folder should I go to create each docker image?
I don't understand that question
How do I know which applications/processes I need to create?
You could create a deployment-diagram and then start from there.
I am building a web app using docker swarm.
Manager machine will have database and load balancer.
Next I have two pieces of software: tornado server, which acts as middle layer between user and node server. They should always be served together. And one tornado server should always talk to one node server.
I want containers to be as isolated as possible (in order to keep scalability), but how I ensure that kind of communication?
Right now my approach is to build two separate images - one for tornado and one for node and then create muli-stage container which connects them both. I do not feel this is optimal as I have to run two start commands in CMD.
What is preferable solution? Can you force docker to couple images (e.g. without specifying IPs)?
There is a link feature in docker compose files: https://docs.docker.com/compose/compose-file/#links. But recently Docker marked it as deprecated and suggests using user-defined networks: https://docs.docker.com/network/.
P.S: Also pay attention to the notes:
- If you define both links and networks, services with links between them must share at least one network in common to communicate.
- This option is ignored when deploying a stack in swarm mode with a (version 3) Compose file.
I am pretty new to Docker. After reading specifically what I needed I figured out how to create a pretty nice Docker setup. I have created some setup where in I can start up multiple systems using one docker-compose.yml file.
I am currently using this for testing specific PHP code on different PHP and MySQL versions. The file structure looks something like this:
./mysql55/Dockerfile
./mysql56/Dockerfile
./mysql57/Dockerfile
./php53/Dockerfile
./php54/Dockerfile
./php56/Dockerfile
./php70/Dockerfile
./php71/Dockerfile
./php72/Dockerfile
./web (shared folder with test files available on all php machines)
./master_web (web interface to send test request to all possible versions using one call)
./docker-compose.yml
In the docker-compose file I setup different containers most refering to the local Dockerfiles, some refering to online image names. When I run docker-compose up all containers start as expected in the configured network configuration and I'm able to use it as desired.
I would first of all like to know how this setup is called. Is this called a "docker swarn" or is such setup called differently?
Secondly, I'd like to make one "compiled/combined" file (image, container, swarn, engine, machine) or however it is called) of this. That I can save without having to depend on external sources again. Of course the docker-compose.yml file will work as long as all the refered external sources are still available. But I'd like to pusblish my fully confired setup as is. How do I do that?
You can publish built images with Docker registry. You can setup your own or use third-party service.
After that, you need to prefix you image names with your registry IP/DNS in docker-compose.yml. This way, you can deploy it anywhere docker-compose is installed (and docker-compose itself can be run as docker container too), just need to copy your docker-compose.yml file there.
docker-machine is tool to deploy to multiple machines, as is docker swarm.
How should applications be scripted/automatically deployed when in LXD containers?
For example is best way to deploy applications in LXD containers to use a bash script (which deploys an application)? How to execute this bash script inside the container by executing a command on the host?
Are there any tools/methods of doing this in a similar way to Docker recipes?
In my case, I use Ansible to:
build the LXD containers (web, database, redis for example).
connect to the containers and deploy the services and code needed.
you can build your own images for example with the services and/or code already deployed and build specific containers from this images.
I was doing this from before LXD had Ansible support (Ansible 2.2) i prefer to use ssh instead of lxd connection, when i connect to the containers to deploy services/code. they comes with a profile where i had setup my ssh public key (to have direct ssh connection by keys ... no passwords)
Take a look at my open source project on bitbucket devops_lxd_containers It includes:
Scripts to build lxd image templates including Apache, tomcat, haproxy.
Scripts to demonstrate custom application image builds such as Apache hosting and key/value content and haproxy configured as a router.
Code to launch the containers and map ports so they are accessible to the larger network
Code to configure haproxy as layer 7 proxy to route http requests between boxes and containers based on uri prefix routing. Based on where it previously deployed and mapped ports.
At the higher level it accepts a data drive spec and will deploy an entire environment compose of many containers spread across many hosts and hook them all up to act as a cohesive whole via a layer 7 proxy.
Extensive documentation showing how I accomplished each major step using code snippets before automating.
Code to support zero-outage upgrades using the layer7 ability to gracefully bleed off old connections while accepting new connections at the new layer.
The entire system is built on the premise that image building is best done in layers. We build a updated Ubuntu image. From it we build a hardened Ubuntu image. From it we build a basic Apache image. From it we build an application specific image like our apacheKV sample. The goal is to never rebuild any more than once and to re-use the common functionality such as the basicJDK as the source for all JDK dependent images so we can avoid having duplicate code in any location. I have strived to keep Image or template creation completely separate from deployment and port mapping. The exception is that I could not complete creation of the layer 7 routing image until we knew everything about how other images would be mapped.
I've been using Hashicorp Packer with the ansible provisioner using ansible_connection = lxd
Some notes here for constructing a template
When iterating through local files on your host system you may need to be using ansible_connection = local (e.g for stat & friends)
Using local_action in ansible with the lxd connection is still
action inside the container when using stat (but not with include_vars & lookup function for files)
Using lots of debug messages in Ansible is helpful to know which local environment ansible is actually operating in.
I'm surprised no one here mentioned Canonicals own tool for managing LXD.
https://juju.is
it is super simple, well supported, and the only caveat is it requires you turn off ipv6 at the LXD/LXC side of things (in the network bridge)
snap install juju --classic
juju bootstrap localhost
from there you can learn about juju models, deploy machines or prebaked images like ubuntuOS
juju deploy ubuntu
Say I have a container that has everything I need to run my web application (such as https://github.com/grigio/docker-stringer for example). How would I go about inspecting the logs for the different services (web server, application server, database server)? With all of the tutorials so far I have only been able to view the logs for the specific command run when starting the container.
One method would be to configure your logs to write to stdout and to use docker logs to retrieve them.
Another option would be to use a bindmount and link to your host file system.