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Create a VPC and connect two VMs to it

This guide creates a VPC with a subnet from the Hikube console, connects two VMs to it and checks that they communicate through their private addresses.

Prerequisites​

  • A Hikube account and a project (see Hikube quick start).
  • Two Linux VMs in this project, at least one of them reachable over SSH (see Create your first VM). You can also create them during this guide.

Step 1: Open the VPC creation wizard​

  1. In the side menu, open Infrastructure > Networking. The Virtual Private Clouds page lists the project's VPCs.
  2. Click Create VPC.

The Create VPC wizard has three steps: General, Subnets and Review.

Step 2: Configure and validate​

General​

Enter the VPC Name, for example vpc-demo (3 to 16 characters: lowercase letters, digits and hyphens, starting with a letter). Click Next.

Subnets​

A subnet is pre-filled with the CIDR Block 172.16.0.0/24.

  1. Name: replace the generated name with app.
  2. CIDR Block: keep 172.16.0.0/24.
  3. Optional: Add a subnet to create more (for example db in 172.16.1.0/24), up to ten.
  4. Click Next.

Review​

The Configuration Summary shows the VPC Name and its Subnets. Click Create VPC.

The console shows VPC Created and returns to the list.

Step 3: Check the status​

In the VPC list, the status of vpc-demo (State column in table view) should change from Provisioning to Ready.

Open the VPC's Actions menu and click View Subnets: the Subnets for vpc-demo page lists app with its CIDR Block 172.16.0.0/24.

Expected result: VPC Ready, subnet app listed.

Step 4: Connect the VMs to the subnet​

For each of the two VMs:

  1. Open VM Instances, click the VM, then Edit.
  2. In Network & Security, under VPC Networks (Secondary), check vpc-demo.
  3. Under Subnets, check app.
  4. Click Save.

For a new VM, make the same selection at the Network step of the Create an Instance wizard.

On the detail page of each VM, Network & Security section:

  • VPC Networks shows vpc-demo and app (172.16.0.0/24);
  • IP Addresses shows a Secondary address in 172.16.0.0/24. Note the one of the second VM.

Step 5: Connect and test​

Connect to the first VM over SSH (command from the SSH Connection block), then list its interfaces:

ip -br addr

Expected result: an additional interface appears (for example enp2s0), without an address: the OS does not configure it automatically.

Enable DHCP on this interface. Example with netplan (Ubuntu):

/etc/netplan/60-vpc.yaml
network:
  version: 2
  ethernets:
    enp2s0:
      dhcp4: true
      dhcp4-overrides:
        use-routes: false
sudo chmod 600 /etc/netplan/60-vpc.yaml
sudo netplan apply
ip -br addr show enp2s0

Expected result: enp2s0 is UP with an address in 172.16.0.x/24, the one shown as Secondary in the console. Do the same on the second VM.

Test communication with the second VM on its private address:

ping -c 3 172.16.0.11

Replace 172.16.0.11 with the Secondary address noted in step 4. The ping should get replies; this traffic goes neither through the Internet nor through the public IP firewall.

Step 6: Quick troubleshooting​

SymptomAction
Invalid CIDR block on creationEnter an IPv4 range in the a.b.c.d/n format, for example 172.16.2.0/24.
Error message mentioning an overlap (overlaps)The range overlaps another subnet of the VPC or a reserved range (10.244.0.0/16, 10.96.0.0/12): choose another range.
The secondary interface has no address in the VMSee Troubleshooting.
The ping gets no replyCheck that both VMs are on the same subnet and that the OS firewall (ufw, firewalld) allows ICMP.

Step 7: Cleanup​

  1. Detach the VMs: Edit > Network & Security, uncheck vpc-demo, then Save.
  2. In Networking, open the VPC's Actions menu and click Delete.
  3. Enter the VPC's name to confirm, then click Permanently delete.

Deleting a VPC also deletes its subnets. It is refused as long as a VM is connected to it: the console shows Cannot delete with the list of the VMs concerned.

Next steps​