I have a requirement where I need to fetch the docker conatiner names, versions and their status whether running or stopped and display it in my web application. Is the docker provides APIs which I can utilize in web app to display all the above details?
My web application is running in a docker container and in the Linux environment.
Yes, you can use Docker Engine API to communicate with the Docker Engine, just like the Docker CLI does.
You can use dockernode to control and query the engine via node.
Related
I've wrote a simple NodeJs (ExpressJs) server that uses Puppeteer to generate PDF files on JSON data being passed to it. While locally everything is working like charm, I'm struggling to run this server on Azure App Services.
I've created a Resource group, within it I've created an App Servces instance (running on Linux) that is connected to my repo at Azure DevOps (via the Deployment Center).
My server has two endpoints:
/ - returns a JSON - { status: "ok" }. I'm using this to validate the running server instance.
/generate-pdf - uses the Puppeteer to generate and return a PDF file.
After successfully starting the App Service instance I'm able to access the "/" route and get a valid response but upon accessing the "/generate-pdf" route the result is "502 - Bad Gateway".
Does my instance require some additional configuration that I haven't done?
Does App Services can not run Puppeteer? Perhaps there is a different service on Azure that I need to use?
Is there a way to automate the process via the Azure DevOps pipeline or release?
Any questions/thoughts/FAQs are more than welcomed. Thanks =)
I'm answering my own question: as was mentioned here https://stackoverflow.com... the Azure App Services does not allow the use of GDI (which is required by Chrome) regardless if you're using Linux or Windows based system. The solution was to put the NodeJs application into a Docker container and manually install Chrome. Once you have a container - just upload it to the Azure App Services and viola!
By default App Servies exposes 80 and 443 ports, so if your application listens on a different port be sure to specify it via the WEBSITES_PORT environment variable.
In my case, I had to upload the Docker image to the Docker hub but you can also set up a pipeline to automate the process.
I've built the Docker image on my M1 Pro and it led to some arch issues when the container was uploaded to Azure. Be sure to add the --platform linux/amd64 in the image-building step if you're building for Linux.
I'm trying to use jsreports.net (following this answer) to generate a pdf in an aspnet core application. Locally it runs fine but when I push it to an azure web app the app fails on start up. Does anyone know if this scenario is possible?
I reproduce your problem and it seems that jsreport uses headless chrome to print pdf. Unfortunately Azure Web Apps running on windows are very restrictive and doesn't allow running headless chrome process. In the other words jsreport.Local won't be able to print pdf in Azure Web Apps running on windows.
Fortunately, Azure Web Apps running in docker with Linux host are using different sandboxing strategy and headless chrome works there. If this is an option for you, enable Linux docker support in your Azure Web App and add to your Dockerfile lines from the docker chapter. Additionally you need to explicitly specify jsreport internal port, because of collision in the environment variables.
For more details, you could refer to this article.
I currently have a simple app consisting of a few micro services (database, front-end node app, user services, etc.) each with its own Dockerfile, and a docker-compose.yml file to get them all up on a local deployment environment. So everything works fine doing docker-compose up.
For production, I was looking for a Heroku (open to other PaaS), which do not support Docker Compose. Not specially nice, but could live with it for now.
The thing is that with Docker Compose on local deployment, the different services are linked via its hostname automatically (if the mongo database service is called "mydatabase", I can do mongodb://mydatabase/whatever within my other services).
So, the question is, what happens with those links on Heroku? What are the best practices to have the different services linked consistently between development and production in this case?
Thanks!
Docker compose creates a docker virtual network which allows you to connect the containers using the container name as a hostname. Heroku doesn't directly support docker-compose, as Docker compose is really intended for
local development on your own machine and not for production.
For production Docker has Docker swarm, which is very similar to Docker compose, however is intended for production environments. You can use the same docker-compose file (called stackfile in swarm) to deploy on swarm.
In docker swarm, you can connect the containers that you have using the same service name just like you would do in docker-compose.
Heroku supports Docker swarm via the DockerHero add-on which you can use to to have your Docker container connected and running on Heroku.
In case anyone else comes across this in their current searches for solutions, Heroku offers an approach using a file similar to docker-compose.yml, called heroku.yml. You simply put it in the root of your project and structure it to call your Dockerfiles: https://devcenter.heroku.com/articles/build-docker-images-heroku-yml
Consider a docker image containing a React UI and a Spring REST app. I'd like to deploy this to Azure web app for containers, where the URL for the instance hits the UI which is being statically served on port 5000 while the Spring app is listening on 8080. The UI communicates with the Spring app via HTTP, hence the requests made by the UI to the Spring app are evaluated on the user's machine (i.e. can't access the Spring app via localhost:8080). However, port 8080 is not mapped in the default run command. Another issue is that there is only one URL for the web app.
The default run command is: (from logging in via FTP and examining docker logs)
docker run -d -p <WEB_APP_PORT>:<UI_PORT> --name ... -e ... <IMG>
Can I run a custom docker run command to expose the UI_PORT and the SPRING_PORT and also set up one web app with two URLs?
If not, are there alternative solutions?
For context:
The final image is built by extending an image which contains only the Spring app (i.e. FROM openjdk:8-jdk-alpine) and installing node and the UI.
An entrypoint.sh script start both the UI and the SPRING APP
The ports exposed in the image are 8080 and 5000.
A diagram of what I'm trying to achieve:
No, you can't do what you want with "Azure web app for containers", that platform lets you run a single container image that is mapped to ONLY one URL, and you can ONLY export web ports (80, 443) to the world, and SSH (2222) to their internal "kudzu" service.
Being "purist", you are describing a "microservice stack", so you have to go with a full container orchestration, like "Azure Container Service" (AKS, using Kubernetes), or "Azure Service Fabric" (which looks it will be awesome when they reach their goals).
However, you could get it done by internally running a "mapping service", like an Nginx proxy which would send "/" to the localhost:8080 UI and /api to localhost:5000 Spring API, or any of the techniques traditionally used for Single-page-Application "routing".
It's a decision between putting all your services inside a single container behind a single URL (microservice in a container) or putting every process in a container on a container orchestration platform (the former is cheaper in time and cost of running it, the later is more "elegant" and flexible but requires more time to build the management and is more expensive to run).
I found a lot of resources online on using docker with Azure virtual machines. But didn't find any on using docker with Azure Webapps. Is this possible?
Things are changing fast in the cloud. Since November 2016, it is now possible on linux web apps to run docker containers. You can read about it here. https://buildazure.com/2016/11/18/deploy-docker-containers-to-azure-web-apps-on-linux
No. Web Apps are a Platform-as-a-Service from Azure which use a bespoke packaging and runtime, you can't just create a Web App, point it to a Docker image and run it as a container.
If you want to run Docker on Azure, you can spin up a VM to use as a single host - you can use an Ubuntu image for Linux containers or a Windows Server 2016 image for Windows containers (currently in preview).
To create a Docker Swarm running on Azure you can use Azure Container Service or Docker for Azure.
No, because a webapp is a PaaS that Azure provides, that allows you to push a website with there settings (to simplify it) with ease.
But, you can push a website onto docker using Azure.
Web Apps, running under App Service, is Webapp-as-a-Service. Nothing to do with Docker. It has its specific methods of code deployment built-in, and does not support Docker images.
That's not to say you cannot have Web Apps and Docker images communicate between each other - you can certainly have, say, your database in a Docker container, being called by your Web App.