Tagged as: DevOps Linux Docker Windows 10

Docker Swarm On Debian and Hyper-V

The servers are based on Debian, have 2 processors each, with 8 gigs of ram, all 3 are running on a single Hyper-V server. I will use certificate authentication with SSH, install sudo, vim, configure networking and setup a swarm instance.

Edward Cooke

• 6 minutes to read

Today, I'm going to go over setting up a 3 node Docker Swarm cluster on Hyper-V.

The servers are based on Debian, have 2 processors each, with 8 gigs of ram, all 3 are running on a single Hyper-V server. I will use certificate authentication with SSH, install sudo and vim, configure networking and setup a swarm instance.

Table of contents

  1. Assumptions
  2. Install Debian in Hyper-V
  3. Install SUDO and VIM
  4. Configure Networking
  5. Configure Certificate Authentication
  6. Install Docker Community Edition
  7. Setup Swarm

Assumptions

  • The Docker hosts will be named Docker1, Docker2 and Docker3
  • Docker1 will be my master node
  • The IP addresses for the Docker servers will be 10.0.0.11 for Docker1, 10.0.0.12 for Docker2 and 10.0.0.13 for Docker3
  • The default gateway is 10.0.0.1
  • The DNS server is 10.0.0.2
  • The Hyper-V server is named Hyperv1
  • The client is named Desktop
  • The client is running Windows 10 and has the OpenSSH client installed
  • The domain name is example.com
  • All passwords are P@ssword1
  • All regular users are user1
  • The Time Zone is Mountain
  • You know how to add DNS entries into your DNS server, this is beyond the scope of this post.

The prerequisites for this are a system with Hyper-V with enough memory and disk space to accommodate the new virtual machines. These virtual machines will also need access to the internet to download the necessary packages for the configuration. I will be assuming that you are running a single Hyper-V server and not clustered and that the Debian install image will be accessible during the creation of the virtual machines. I am also assuming that your Hyper-V server is not on your local desktop, if it is, ignore the parts of the PowerShell commands that specify the computer name.

I recommend that you have a local DNS server that you can put host entries into so you can access the Docker servers by name instead of IP address, though this is not necessary. If you don't have one, you will need to modify some of the configuration examples and commands to specify the IP addresses instead of using host names.

Install Debian in Hyper-V

  1. Download the latest Debian install image from the official Debian site, https://www.debian.org. At the time of this writing, it is 9.9.0
    • You only need the small CD image, we're not installing anything that is on the big image
    • Once downloaded, put it in a place that the Hyper-V machine has access to.
  2. Create the 3 Hyper-V virtual machines
    • Name them Docker1, Docker2, Docker3
    • Use Generate 2
    • Assign 8 gig (8192 MB) of memory, I do not recommend dynamic memory for this
    • Connect them to your network
    • Setup the storage the way you need it for your environment, I leave them at defaults
    • Attach the Debian cd image you just downloaded
  3. On each of those 3 VM's increase the processor count to 2
    1. Open the Settings on the VM
    2. Go to Processor
    3. Change the virtual processor count to 2
    4. If you need to assign a VLAN Id to the NIC, do that now
    5. Click OK
  4. Disable Secure Boot on the VM's so that Debian will start, on Desktop
    1. Open PowerShell
    2. Execute the following:
      Set-VMFirmware -EnableSecureBoot $false -VMName Docker1 -ComputerName hyperv1
Set-VMFirmware -EnableSecureBoot $false -VMName Docker2 -ComputerName hyperv1
Set-VMFirmware -EnableSecureBoot $false -VMName Docker3 -ComputerName hyperv1
  5. Start each Docker VM and connect to them
  6. Install Debian, on each Docker VM
    1. Leave it at Graphical Install and press Enter
    2. Setup localization
      1. Choose your language and click Continue, I'm assuming it's English
      2. Choose your country and click Continue, I'm assuming it's United States
      3. Choose your keyboard and click Continue, I'm assuming it's American English
    3. Setup the hostname
      1. Assign the hostname, use the name of the VM to make it easy, Docker1, Docker2 and Docker3, and click Continue
      2. Set the domain name, example.com, and click Continue
    4. Set the root password
      1. Type the password for the root user, P@ssword, and click Continue
    5. Setup the primary user
      1. Type the name of the user, user1, and click Continue
      2. Type the user name, user1, and click Continue
      3. Type the password, P@ssword, and click Continue
    6. Set the time zone
      1. Choose your time zone, Mountain, and click Continue
    7. Partition the disk
      1. Leave at Guided - use entire disk and click Continue
      2. Leave at the first disk and click Continue
      3. Leave at All files in one partition and click Continue
      4. Leave at Finish partitioning and write changes to disk and click Continue
      5. Change Write changes to disk to Yes and click Continue
    8. Let the system install it's packages, this may take a few minutes
    9. Leave Scan another CD or DVD at No and click Continue
    10. Configure the package manager
      1. Leave the Debian archive mirror country at United States and click Continue
      2. Leave the Debian archive mirror at ftp.us.debian.org and click Continue
      3. Leave the proxy blank, unless you have one and need to set it.
    11. Leave the Participate in the package usage survey at No and click Continue
    12. Set the Software Selection
      1. Select only SSH server and standard system utilities. Uncheck everything else
      2. Click Continue
      3. Let it finish installing everything, this may take a few minutes
    13. Click Continue, the machines will automatically unmount the installer image and reboot into the installed Debian OS

Debian is now installed in 3 Hyper-V virtual machines with 8 gigs of RAM, 2 cores and up to 128 gigs of drive space.

Install sudo and vim

On each Docker server:

  1. Login, username is user1, password is P@ssword
  2. Get root access the password is P@ssword:
    su -
  3. Update apt
    apt update
  4. Install applications, press Y when asks you to continue
    apt install sudo vim
  5. Add user1 to the sudo group:
    usermod -a -G sudo user1

Configure Networking

On each Docker server, still as root:

  1. Execute vi /etc/network/interfaces
  2. Replacing the Docker Host IP with the correct one for the host (up at the top), replace everything below the # The primary network interface with the following
    # The primary network interface
auto eth0
iface eth0 inet static
        address 10.0.0.11
        netmask 255.255.255.0
        gateway 70.89.247.238
        dns-nameservers 10.0.0.2
  3. Write and exit vi, press escape, type :wq press enter
  4. Reboot, shutdown -r now

If you haven't already, now is a good time to set the host entries in your DNS server if you have one. In the commands

Configure Certificate Authentication

On your client

  1. Create the private/public keys
    • In PowerShell execute the following:
      cd ~
mkdir .ssh -ErrorAction SilentlyContinue
ssh-keygen -t ed25519 -b 4096 -f .ssh/docker1.example.com_id
ssh-keygen -t ed25519 -b 4096 -f .ssh/docker2.example.com_id
ssh-keygen -t ed25519 -b 4096 -f .ssh/docker3.example.com_id
notepad .ssh/config
    • If notepad says it is a new file and asks if you want to create it, click Yes
  2. Add the following to the end of the config file
    Host docker1.example.com
    Hostname docker1.example.com
    User user1
    IdentityFile ~/.ssh/docker1.example.com_id
Host docker2.example.com
    Hostname docker2.example.com
    User user1
    IdentityFile ~/.ssh/docker1.example.com_id
Host docker3.example.com
    Hostname docker3.example.com
    User user1
    IdentityFile ~/.ssh/docker1.example.com_id
  3. Close notepad

For each Docker server, still on the client in PowerShell

  1. Get the public session key
    get-content ~/.ssh/docker1.example.com_id.pub
    Copy the result, should be something like ssh-ed25519 LOTS OF STUFF
  2. Start a new ssh session
    ssh docker1.example.com
    • The ssh command will most likely ask if you want to trust the server, type yes press enter
    • The password is P@ssword
  3. Add the key to the authorized_keys file and set the correct permissions.
    mkdir .ssh
echo "<<public session key, include the quotes>>" > ./ssh/authorized_keys
chmod 0600 ./ssh/authorized_keys
  4. Exit the session
    exit

If you created your private key without a password you can now get into your Docker servers without a password from your client., You can test this by doing remoting into the server again.

ssh docker1.example.com

Install Docker Community Edition

There's really no need to duplicate the detailed installation guide from Docker's site. Plus, the installation instructions for adding their apt repository may change. So here is a link if you haven't already seen it during your search for installing Docker. https://docs.docker.com/install/linux/docker-ce/debian/#install-using-the-repository

The previous steps get you to the point where the commands and instructions they give you will work the way they should. You will want to run through the installation on each of your Docker servers.

After you have finished, installing Docker CE on your servers, we'll go over installing Swarm in our environment in the next section.

I will assume from that you added user1 to the docker group.

Setup Swarm

You should now have a simple, plain installation of Docker CE on each of your servers. You also have the networking configured, sudo and vim install, along with certificate authentication setup and working. Our user, user1, should also be added to the docker group. If you didn't, the command is:

sudo usermod -aG docker user1

We need to initialize the Swarm instance. On the master server Docker1

docker swarm init

This will output a few lines, the one we're interested in is the docker swarm join line. It should look something like this:

docker swarm join --token SWMTKN-1-BUNCHOFSTUFF 10.0.0.11:2377

I don't like hard coded IP addresses and have a DNS server, so we can slightly modify the line to use the host name, docker1.example.com. If you don't have a DNS server, don't modify the line. Copy that line, paste it into notepad, and replace the IP address at the end with docker1.example.com. Copy the result and run it on docker2 and docker3.

docker swarm join --token SWMTKN-1-BUNCHOFSTUFF docker1.example.com:2377

The result

This node joined a swarm as a worker.

Conclusion

That's all there is to getting a multi-node swarm instance going in Hyper-V running on Debian. It's not very complicated once you get Debian running in Hyper-V. The hardest part to figure out was disabling the Secure Boot feature for the VM in Hyper-V. You need to disable it otherwise the virtual machine will sit there during boot waiting for the network.