The frontend has to communicate with the database, otherwise, it just won't work. There are two services, one is the web server that serves the frontend, and another is the backend, the database. Depending on the purpose of the software, one service may need to communicate with another.įor example, consider WordPress. Each of these softwares is broken down into microservices and then packaged as containers.
Software can have a multitude of purposes, from possibly simple text processing to a full web server, hosting your private files. How docker containers communicate?ĭocker is a tool for packaging and delivering software to the masses using containerization technology. I'll explain that to you in the next section followed by some other methods of getting the IP address of a running docker container. To understand that, you need to understand how containers communicate with each other. You may also use grep command to get just the lines matching the string "IPAddress".ĭon't be alarmed if your container has more than one IP address. Go towards the end and look into the Networks section to get the container's IP address. The inspect command gives you many details about the container you are inspecting. Īfter a reboot, I was able to map docker volumes to my Unraid's appdata share without any issues.Don't know the container's name or ID? Use the command sudo docker ps. I then SSH'd into the CoreOS VM and modified the mount unit. Under NFS Security Settings, I set Export to Yes, Security to Private, and entered a rule to allow the CoreOS VM to read and write to the share. In the Unraid web interface, I enabled the NFS protocol and headed to my appdata share settings. I found that replacing the 9p mount with an NFS mount resolved the issues. While trying to deploy some Docker containers with volumes mapped to my Unraid's appdata share over the 9p mount, I ran into some permission problems writing to the share. sudo coreos-install -d /dev/vda -C stable -i ignition.jsonĪfter rebooting, you should be able to SSH into the VM, access Unraid's appdata share, and use Docker.
Return to the VM and install CoreOS to the disk and reboot the VM. sudo passwd coreįrom your computer, use SCP to transfer the file.
We will need to set a password for the 'core' user so that we can transfer the Ignition file to the VM. Once the VM starts up, connect to it with Unraid's VNC Remote. Leave "Start VM after creation" checked, and click Create. I also went ahead and added an Unraid share pointing to '/mnt/user/appdata' with a mount tag of 'appdata' as I did with Ubuntu Core.
Give it two CPUs, 2048 MB memory, change the BIOS to SeaBIOS, select the CoreOS ISO as the OS Install ISO, and a 32G raw vDisk with a VirtIO bus. Log into your Unraid server's web GUI and create a VM for CoreOS. ct-v0.9.0-x86_64-unknown-linux-gnu -in-file config.yaml -out-file ignition.json -pretty Installation Options=trans=virtio,version=9p2000.L,_netdevĪfter creating the config file, convert it with the Config Transpiler. networkd:ĭescription=CUBE:/mnt/user/appdata to CORE:/mnt/appdata In this config file, I configure: the network with a static IP address modify the built in "core" user by adding authorized SSH keys create a user for myself with a password, authorized SSH keys, and added myself to the "wheel" and "docker" groups changed the hostname and created a folder for an "appdata" mount and implemented the same 9p mount that I used on the Ubuntu Core VM. This is done by creating and converting a Container Linux Config file using the Config Transpiler. Next we need to create an Ignition configuration file to configure the machine during installation. Once the ISO has been downloaded, move it into your Unraid's ISO share. Preparationīefore we start, we need to download the CoreOS stable ISO. CoreOS is another lightweight operating system but it's main focus is on Docker instead of Snaps like Ubuntu Core. After trying out Ubuntu Core as an alternative Docker host, I decided that I would try CoreOS as well.