Set up UniFi Controller on Google Cloud Platform

Google offers one free virtual machine on Google Cloud Platform. This script will make setting up a UniFi Controller on GCP a breeze and it includes all the goodies. No command line required, everything is done in the GCP Console and it takes ten minutes total. You should try this!

The script I have created will set up an UniFi Controller on GCP with these extras:

  • Automatically acquire and install a Let’s Encrypt certificate to relieve you from HTTPS certificate warnings. For a certificate you need to have a domain name for your controller, dynamic or static.
  • Dynamic DNS support to help you set up the domain name.
  • You don’t need to type https://your.server.dns:8443 every time. You just type the DNS name of your controller and it will be redirected to HTTPS port 8443 automatically.
  • Backup files will be copied to a Google Storage bucket for offline storage.
  • Fail2Ban protects your controller from attackers trying to brute force the password: the IP address of the offender will be denied access for an hour after every three failed attempts.
  • The free tier GCP micro instance comes with only 600MB of memory. The script will create a swap file to accommodate the controller.
  • The underlying Linux system and UniFi Controller will be automatically updated to the latest stable releases. If an update requires a server restart or a reboot, you can set the time zone to adjust the timing. The reboot will occur after 04AM local time. A reboot will make a captive wireless guest portal inaccessible for a couple of minutes so you don’t want it to happen during peak hours.
  • If the MongoDB database supporting UniFi Controller needs repairing, a reboot will do the trick. There is a support script to run the repair commands as needed before the controller starts.
  • HAVEGEd will store entropy for encryption. Without sufficient entropy available the boot time can be 30 minutes or more.

None of this will cost a dime to try out. Let’s begin!

1. Preliminaries

Take a backup of your current controller in Settings > Maintenance. This is always a good idea. You may also want first to improve your password. In Google Cloud your controller can be accessed by anyone who guesses your username and password. You don’t want that. Fail2Ban will lock the IP address for an hour after three failed attempts, but it won’t help if your password is guessable.

A proper SSL certificate requires a DNS name that points to your controller. You can register your own domain or use one of the free ones that dynamic DNS providers offer. If you want to use a dDNS service, you need to set it up first. There are links to some providers at the end. If you control your DNS yourself you won’t need dDNS.

Next you have to create an account on Google Cloud Platform. You will need a credit card for this, but the micro instance that Google offers for free is sufficient for a small UniFi Controller and the free 5GB on Cloud Storage is plenty for the backups. Google does not guarantee this offer will run forever, but it has run for years now and they will certainly let you know if this changes. The current price for a micro instance is $4.28 per month, if you need to run another for example.

First of all, use a good password or set up two factor authentication. If someone breaks into your account the intruder could create a huge bill in just a few hours. You can also set a spending limit in Billing > Budgets & Alerts. Create a new budget for the whole billing account and set a budget. $50 or even $10 should be enough, if you ever want to do some testing on an extra controller for a few hours. The budget feature won’t protect you from an intruder breaking into your account, however. The first thing the intruder would do is to remove the limit.

If you set up budget alerts (50%, 90% and 100% by default) you need to nominate yourself to a billing administrator to receive the alert emails. This is done in IAM & Admin > IAM section. Locate your identity in the list and click in the Roles column. Check Billing > Project Billing Manager to add this role to your identity.

2. Create a Storage Bucket (optional)

UniFi Controller will create backups automatically. The default is once a month, but you can change this in UniFi Controller > Settings > Auto Backup. I run backups once a week and keep the last 26 or a half year’s worth. These backups are stored on the computer the controller runs on. If this computer is lost for some reason, so are the backups. You should store them somewhere else and a Google Storage bucket is the perfect place. If you create a bucket the script will save the backups in the bucket daily.

In GCP Console switch to Storage > Browser and create a new bucket. The bucket name has to be globally unique, so all the obvious ones are already in use. Use something like petri-office-unifi-backup. For the free offer select Regional as the Storage class and choose a Regional Location in the U.S. I am in Europe and east coast is marginally closer, so I chose it.

3. Set Up the Virtual Network

This is something you will need to do only once. All your future UniFi controllers will use the same network settings.

Switch to VPC Network > Firewall Rules. Create a new firewall rule and name it allow-unifi for example, the name isn’t important. In the Target tags field enter unifi. You can use any name for the tag, but you will need to remember it for the next step. In the Source IP range type to denote any address. In the Protocols and ports section select Specified protocols and ports and copy this into the field:


Switch to  VPC Networks > External IP Addresses and click on Reserve Static Address. You need to give a name for the address, choose the region where your virtual machine is going to run and click Reserve. I suggest you use the same region as the Storage bucket. You can’t attach the address yet, since you haven’t yet created the virtual machine. (Google will charge for the static addresses while they are not in use. The plan is to run the controller non-stop so this is not an issue. Just remember to release the address if you don’t need it any longer.) Copy the IP address for later use.

4. Create the Virtual Machine

In Compute Engine > VM Instances create a new instance. You can name it anything you like. Select a Zone in the U.S. for the free offer. You need to place the VM in a zone that is in the same region as the static address. The Machine type should be micro for the free instance. By default the Boot disk is 10GB which suffices, but it is tricky to expand afterwards. The free offer is 30GB but I prefer to set the boot disk to 15GB in case I need to run another VM. To change the size, click on Change and set the size. The script is designed to run on Debian Linux so don’t change that. Click Select to save.

If you created a bucket for the backups, you need to allow the virtual machine to write to Google Storage. The default permission is Read Only. In Access Scopes choose Set access for each API. In the list that appears change Storage to Read Write.

No need to select the HTTP and HTTPS options in the Firewall section. You created your own firewall rules already.

Click on Management, disks, networking, SSH keys to open advanced options. On the appearing Management tab add the following Metadata key/value pairs. The first one is mandatory: the script that does the magic. All the others are optional and the order doesn’t matter. There is no way to do any error checking or report script failures, some feature will just not work if the metadata is erroneous. You can come back and change them if necessary. The changes will take effect after next reboot. See the Maintenance section at the end for how to reboot.

Key Value Purpose
startup-script-url gs://petri-unifi/ Required!
ddns-url http://your.dyn.dns/update.php?key=xxxxx Helps you access the Controller
timezone Europe/Helsinki Lets you adjust the reboot hour
dns-name your.server.dns Required for HTTPS certificate
bucket your-bucket-name-here Required for offline backups

Click on the Networking tab and add unifi to the Network Tags field. This tag ties the firewall rules you created earlier to this virtual machine instance. This step is easy to forget, but missing it will prevent access to your controller! Click on Default under Network Interfaces and choose the static IP address you created earlier as the External IP.

Click Create. Go get coffee. Even if the virtual machine appears to be running, the script is not done yet. It usually takes less than five minutes, but give it ten.

5. Set Up the Controller

Connect to your new controller. On the first screen of the UniFi wizard click restore from a previous backup and upload the latest backup. Wait for the restore to complete. Log on to the new controller using your old username and password. In Settings > Controller add the DNS name or the IP address of the new controller to Controller Hostname/IP field and check Override inform host with controller hostname/IP. Confirm the change. Click Apply Settings.

Connect to your old controller. Do the same change in Settings > Controller and add the DNS name or the IP address to Controller Hostname/IP field and check Override inform host with controller hostname/IP. This setting is for the current devices that are already associated with the current controller. Now they will start to contact the new controller in Google Cloud.

Connect to your new controller again. Check the devices page to see whether the devices come online eventually. If they don’t, you may have to force reprovisions them on the old controller. In that case go to the Devices page on the old controller, select each device in turn and on the Config tab click Provision under Manage Device.

How to Set Up a New Network with a GCP Controller

If you are starting from scratch you won’t have any controller backup to transfer to the GCP based UniFi Controller. In that case you have three alternatives:

  1. Install a temporary controller on a local computer, set up the network and transfer the controller to GCP as outlined above.
  2. If you want to do a pure cloud based installation, you’ll need to tell the devices the address of the controller. If you have an UniFi Security Gateway connect its WAN interface to the Internet and your laptop directly to the LAN interface. Connect to the USG with a browser ( and configure the inform URL to http://your.server.dns:8080/inform. Once you have adopted the USG in the controller other UniFi devices will appear in the controller as you start to connect them.
  3. If you have some other router than an USG, you can either set your DNS server to resolve name unifi to the IP address of your cloud controller or set the DHCP option 43 in your DHCP server. There are examples of both in Ubiquiti’s L3 Adoption Guide. The last resort is to SSH to each device in turn and use command
    set-inform http://your.server.dns:8080/inform.

Maintenance and troubleshooting

If your devices won’t switch to the new controller the reason is usually either in the firewall or DNS. Is your VPC firewall rule correct and does the network tag of the virtual machine match the tag on the rule? Is your DNS name correct both in the metadata and in both controllers’ Override Inform Host fields and does the DNS name point to the correct IP address? In either case the devices will try to connect for several minutes before reconnecting to the old controller. Sometimes it takes hours for DNS to settle, depending on the time-to-live settings. In that case let it sit overnight and force provision the devices next morning.

Let’s Encrypt limits the number of certificates issued per domain to five per week (at the time). This usually isn’t an issue, but if you use the free domains offered by dDNS providers, the most popular domains will have used this week’s five certificates already. In this case the script will try to acquire a certificate once an hour until it succeeds. You will see certificate warnings at first but the address bar should eventually turn green. You can also anticipate this and choose a less popular domain (or register your own).

Don’t set up two controllers to back up to the same bucket. They will delete each other’s backups. You can either create a new bucket or create folders inside the bucket. In the metadata set bucket to your-bucket/foldername.

The Cloud Console will typically start displaying a recommendation to increase performance by upgrading to a bigger virtual machine (at cost), even though the CPU utilisation graph typically stays below 15%. Apparently the updates the devices send cause very short spikes, because occasionally the devices report that the controller is busy. This may cause some inaccuracies in the reports, I am not certain. If you can live with that, just dismiss the suggestion. In my experience the the micro instance can serve at least the same 30 devices a Cloud Key can. You can also use this script on any virtual machine type you like. When you select the machine type you see the cost per month. You get a better price if you can commit to use the resource for 1 or 3 years.

If the controller appears to be malfunctioning the first remedy is to reboot it. A reboot is also the way to re-run the script if you made changes to the metadata. The safe way to reboot is to Stop and then Start the virtual machine. This won’t change the IP address since you have reserved a static address. Don’t use the Reset button. A Reset will immediately restart the virtual machine, which may damage the UniFi database and/or the Linux filesystem (if you are really unlucky).

The automatic Linux update won’t do major version upgrades. Every couple of years it is wise to upgrade the underlying Linux operating system. The Cloud Way is to create a new UniFi controller:

  1. Take a backup of the old controller.
  2. Create a new bucket (or folder).
  3. Remove the static IP address from the old virtual machine (VPC Network > External IP Addresses and Change to None)
  4. Create a new virtual machine as outlined above and restore the backup
  5. Delete the old virtual machine
  6. Done! Since the IP address is the same there is no need to update any settings and the turnover is immediate.

If your controller starts to act up and rebooting doesn’t help, just create a new one. Just like upgrading the underlying Linux, create a new virtual machine. If you cannot connect to the old controller to retrieve the backup, use the latest auto backup in the storage bucket. That’s what they are for. Don’t fall in love with your virtual machine, you should treat them like pencils: very useful but replaceable.

Google currently offers for free one micro instance with 30GB of disk space and 5GB of bucket storage in the U.S. regions. Both come with monthly 1GB of free egress (i.e. outbound) data transfer with China and Australia excluded. Egress data is used when you download backups to your computer and when your devices download upgrades from the controller. The static IP address is free as long as it is attached to a running virtual machine. You will be charged if you exceed these limits, but typically the charges are minuscule. For example when you upgrade your Linux you will run another micro instance for a while. The budget feature should protect you from nasty surprises.


Some dynamic DNS providers and how their single line update URLs look like:

  • DNSPark
  • DynDNS
    https://{user}:{updater client key}{hostname}
  • EasyDNS
  • NameCheap[host]&domain=[domain_name]&password=[ddns_password]
  • Sitelutions
  • ZoneEdit


Leave a Reply

Your email address will not be published. Required fields are marked *