SUN – Stretched Unified Network joins your servers in different datacenters into one private network. Servers in Datacenter A and Datacenter B share one subnet, as if they were plugged into the same switch.
What you get
- One subnet everywhere. Servers in every SUN datacenter share the same subnet and broadcast domain. You can keep a server’s SUN address when you move it between SUN datacenters.
- Encrypted between sites. Traffic between datacenters is encrypted.
- Yours alone. Your SUN is private to your account. It is never reachable from the internet or from other customers.
- Packet size set for you. The packet size (MTU) is set automatically and cannot be changed. You do not configure it on the server.
Typical uses: database replication, active-active clusters, disaster recovery, and moving servers between datacenters without changing their addresses.
Before you start
- SUN is switched on per account by our team. Until then, Networking → SUN shows a request form.
- SUN is available only in some datacenters. A server in another datacenter cannot join, and its SUN tab says so.
- Your account can have one SUN network. All your SUN servers share it.
- Both the classic and the new portal layout show the same SUN screens, under Networking → SUN and in each server’s Networking → SUN tab.
Request access
- Open Networking → SUN.
- Write a line about what you will use it for (optional) and select Request SUN access.
- The page shows “pending review” with the date of your request. We email you when it is decided, and the page updates by itself.
- If the request is rejected, the page shows the reason. You can select Request again at any time.
Create your SUN network
Once access is approved, Networking → SUN shows Choose Configuration Options.
- Pick the IP range:
- Use the SUN default range (recommended):
10.210.0.0/16, room for tens of thousands of servers. - Manually configure an IP range: enter a private IP prefix and a size from
/16to/28.
- Use the SUN default range (recommended):
- Enter a name (up to 200 characters) and, if you like, a description.
- Select Create SUN Network.
Rules for your own range, in plain words:
- It must be a private range:
10.0.0.0/8,172.16.0.0/12or192.168.0.0/16. - The prefix must be the first address of the range. For example
10.20.0.0for a/16, but not10.20.0.1. - It cannot overlap any of your VPC networks.
- It cannot overlap the floating-IP range (shown on the page).
- It cannot overlap
10.250.0.0–10.254.255.255, which is reserved.
The page shows the first and last usable address and how many addresses you get before you create. A few addresses at the start and the end of every range are kept by the platform, so the first usable address is not the first address of the range. If a rule is broken, it tells you which one. If your account already has a VPC network in 10.210.x.x, the default range is refused with a message and the form switches to the manual option: choose another range.
You cannot change the range of a SUN network after it is created. To use another range, delete the network (it must be empty) and create a new one.
Add servers
- Open your SUN network from the list and select the + next to Resources, or open a server’s Networking → SUN tab and select Add to SUN.
- Choose the server and confirm. Only servers in a datacenter where SUN is available are listed.
Adding a server may restart it briefly. The page says “Adding the server to SUN…” and then “Server added to SUN” once the server really is in the network. The server gets an address from the range; you can change it afterwards.
Controls for each server
In the servers table of your SUN network, and in the server’s own SUN tab:
| Control | What it does |
|---|---|
| Connected | Switches the server’s SUN connection off or on without removing it. |
| Firewall | Applies the server’s firewall groups to SUN traffic. |
| Edit IP | Changes the server’s SUN address. It must be inside the range, other than the network and broadcast addresses. This may restart the server briefly. |
| Remove | Takes the server out of SUN. The server keeps running; only its SUN connection is removed. |
You can also rename the network (double-click the name) and copy the range, the first address and the last address.
Delete a SUN network
Remove all servers from the network first, then use the Delete card on its page.
Limits
- One SUN network per account.
- Only in datacenters where SUN is available.
- The packet size (MTU) is set automatically and cannot be changed.
- A SUN network cannot be used for Kubernetes clusters, load balancers or managed databases.
- A SUN network cannot be your default network, and a gateway cannot be set on a SUN network. SUN is a flat private segment (Layer 2), so the servers table shows “— (Layer 2)” in the Gateway column.
If your access is switched off
If our team switches SUN off for your account, servers already in your SUN network stay connected. You can still use the Connected and Firewall switches, edit addresses, remove servers and delete the network. You cannot create a new SUN network or add servers until access is back, and the page shows the request form again.
