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Let's Encrypt certificates

PiKVM uses self-signed SSL certificates out of the box. If you have a domain name, you can use Let's Encrypt certificates.

Usually Let's Encrypt certificates are issued and updated automatically using Certbot, however, since PiKVM uses a read-only file system, special tools around Certbot are required to work with certificates. KVMD 3.117 provides them.


This feature is available on images as old as 2022.06.19 since it requires PST storage partition on SD card. Ports 80+443 need to be opened if you are port forwarding for this to work properly.

Basic setup

  1. Update the OS and make sure that you are using a new image with PST storage.

    Updating PiKVM OS

    To update, run following commands under the root user:

    [root@pikvm ~]# pikvm-update

    If you encounter an error like:

    [root@pikvm ~]# pikvm-update
    bash: pikvm-update: command not found

    It's most likely you have an old OS release. You can update the OS as follows:

    [root@pikvm ~]# rw
    [root@pikvm ~]# pacman -Syy
    [root@pikvm ~]# pacman -S pikvm-os-updater
    [root@pikvm ~]# pikvm-update

    Next time you will be able to use the usual method with pikvm-update.

    # kvmd-pstrun -- true

    If the storage is not available, you need to reflash the OS image to the latest one from our official website.

  2. Switch filesystem to RW and obtain the certificate (for example, The method depends on the network configuration. In the simplest case, if PiKVM is open for access from the Internet, it is recommended to use the webroot. Another examples will be described below.

    # rw
    # kvmd-certbot certonly_webroot --agree-tos -n --email -d
  3. Install the certificate for KVMD-Nginx and (optionally) KVMD-VNC. Running services will be restarted/reloaded automatically. Switch filesystem to RO.

    # kvmd-certbot install_nginx
    # kvmd-certbot install_vnc
    # ro
  4. Check the renewal immediately, just for testing:

    # kvmd-certbot renew --force-renewal
  5. Enable automatic certificate renewal:

    # rw
    # systemctl enable --now kvmd-certbot.timer
    # ro

Cloudflare DNS

This example shows that PiKVM may not be accessible from the internet, but you can still get a certificate if you use Cloudflare DNS.

  1. Switch filesystem to RW and install the Cloudflare DNS plugin:

    # rw
    # pacman -S certbot-dns-cloudflare
  2. Prepare the environment for the DNS plugin (place the auth data):

    # kvmd-pstrun -- mkdir -p /var/lib/kvmd/pst/data/certbot/runroot
    # kvmd-pstrun -- nano /var/lib/kvmd/pst/data/certbot/runroot/.cloudflare.auth
    # kvmd-pstrun -- chmod 600 /var/lib/kvmd/pst/data/certbot/runroot/.cloudflare.auth
    # kvmd-pstrun -- chown kvmd-certbot: /var/lib/kvmd/pst/data/certbot/runroot/.cloudflare.auth
    See certbot-dns-cloudflare's doc here about the content of .cloudflare.auth.
  3. Obtain the certificate:

    # kvmd-certbot certonly \
       --dns-cloudflare \
       --dns-cloudflare-propagation-seconds 60 \
       --dns-cloudflare-credentials /var/lib/kvmd/pst/data/certbot/runroot/.cloudflare.auth \
       --agree-tos \
       -n \
       --email \
  4. Next follow the basic guide starts at step 3.

Route53 DNS

This example shows that PiKVM may not be accessible from the internet, but you can still get a certificate if you use AWS Route53 DNS. Make sure you are running an image newer than 2022.06.20 and kvmd version 3.119-1 or greater.

  1. Switch filesystem to RW and install the Route53 DNS plugin:

    # rw
    # pacman -S certbot-dns-route53
  2. Configure Your AWS User For the certbot_dns_route53 plugin to work it needs to be able to connect to AWS using an access key with the correct permissions.

    To do this securely you’ll want to create a new AWS user that only has the necessary permissions it needs to work.

    You can find instructions for creating a user here. The basics of it is you’ll want a user with Programmatic access (not console), add it to a group (I created a new one just for this user and any future certbot users I might need).

    The user will need specific permissions that are required to allow the certbot plugin to create the necessary CNAME records. These can be added by manually selecting them from a very long list or you can use the json view to give it the following permissions.

    "Version": "2012-10-17",
    "Statement": [
          "Effect": "Allow",
          "Action": ["route53:ListHostedZones", "route53:GetChange"],
          "Resource": ["*"]
          "Effect": "Allow",
          "Action": ["route53:ChangeResourceRecordSets"],
          "Resource": ["arn:aws:route53:::hostedzone/YOURHOSTEDZONEID"]

    Make sure you replace YOURHOSTEDZONEID with the instance ID of your hosted zone.

    Once the user is created don’t forget to download and save your access key and secret access key (somewhere secure, these are as sensitive as your passwords).

  3. Setup credentials:

    We now need to put the AWS credentials on the PiKVM so the certbot can use them.

    # kvmd-pstrun -- mkdir -p /var/lib/kvmd/pst/data/certbot/runroot

    Copy and paste your AWS credentials into the nano editor and save the file.

    # kvmd-pstrun -- nano /var/lib/kvmd/pst/data/certbot/runroot/.route53.auth

    Here is an example .route53.auth file. Replace the placeholders with the access key and secret access key that you just saved from AWS and fill them in.


    Update permissions:

    # kvmd-pstrun -- chmod 600 /var/lib/kvmd/pst/data/certbot/runroot/.route53.auth
    # kvmd-pstrun -- chown kvmd-certbot: /var/lib/kvmd/pst/data/certbot/runroot/.route53.auth
  4. Obtain the certificate:

    # export AWS_SHARED_CREDENTIALS_FILE="/var/lib/kvmd/pst/data/certbot/runroot/.route53.auth"
    # kvmd-certbot certonly \
       --dns-route53 \
       --agree-tos \
       -n \
       --email \
  5. Enable automatic certificate renewal:

    Create the file: /etc/conf.d/kvmd-certbot with the following contents so the renewall service can find the authentication file containing the AWS credentials:


    Now enable the renewal service:

    # systemctl enable --now kvmd-certbot.timer


ACME DNS is a "Limited DNS server with RESTful HTTP API to handle ACME DNS challenges easily and securely." The acme-dns-client works, in conjunction, with Certbot (kvmd-certbot) to enable DNS-01 challenge support via ACME DNS.

These instructions are for how to install and use the acme-dns-client with ACME DNS for PiKVM.


  • ACME DNS is already set up and functioning in the environment
  • ACME DNS Server is
  • PiKVM Fully Qualified Domain Name (FQDN) is
  • PiKVM is running on a supported Raspberry Pi using the PiKVM OS (which is 32-bit as of the writing of this documentation)
  • All configuration examples below are as user root via a terminal session to PiKVM

Not in Scope

  • Installation and Setup of ACME DNS Server


  1. Ensure that Step 1 from Basic Setup has been completed
  2. Visit the Releases page to get the download URL for the latest acme-dns-client release (PiKVM OS is 32-bit, which is linux_armv6)
  3. Install acme-dns-client

    The acme-dns-client is not distributed by pacman and is a manual installation. The steps below are for:

    • Creating a folder for acme-dns-client
    • Downloading and extracting the acme-dns-client TAR from Github
    • Moving the acme-dns-client binary to the created folder
    • Cleaning up files from the download
    • Creating the necessary persistent symbolic link to allow acme-dns-client to be ran
    • Initialize acme-dns-client


    Make sure to replace the URL below with the one gathered from Step 1.
    As of the writing of this documentation:
    - The latest (and demonstrated) version is v0.3
    - (Demonstrated) Platform is linux-armv6

    # mkdir /etc/acmedns
    # curl -LO
    # tar -zxvf acme-dns-client_0.3_linux_armv6.tar.gz
    # mv acme-dns-client /etc/acmedns/acme-dns-client
    # ln -sf /etc/acmedns/acme-dns-client /usr/local/bin/acme-dns-client
    # rm LICENSE acme-dns-client_0.3_linux_armv6.tar.gz
    # acme-dns-client
  4. Register acme-dns-client with ACME DNS


    This is interactive, follow instructions for creating and verifying the appropriate CNAME record.

    # acme-dns-client register -d -s

    Once registration is complete ownership of clientstorage.json must be changed to kvmd-certbot.

    # chown kvmd-certbot:kvmd-certbot /etc/acmedns/clientstorage.json


    If using acme-dns-client on an internal/private domain with an ACME compatible Certificate Authority do not forget to add -ns <dns-server-ip>:<dns-server-port> to acme-dns-client register

  5. Register Certbot

    # kvmd-certbot register
  6. Request Certificate via Certbot

    # kvmd-certbot certonly --manual --preferred-challenges dns --manual-auth-hook 'acme-dns-client' -d


    If using an ACME compatible Certificate Authority (other than Let's Encrypt) do not forget to add --server to kvmd-certbot

  7. Follow steps 3 through 5 under Basic Setup to complete setup and renewal of certificates

Wireguard proxy

If you don't have public IP, and you don't want to put your API keys in PiKVM, you can forward HTTP traffic over wireguard. To Let's Encrypt you'll appear to serve ACME challenges from a host they can reach from the Internet (e.g. VPS), to which you'll connect over wireguard.


  • FQDN of your pikvm is;
  • FQDN of the proxy VPS is acme-proxy.example;
  • public IP addresses of VPS are and 2001:db8::1;
  • internal (wireguard) IPv4 address of the PiKVM is


  1. Setup wireguard and ensure it's working.

  2. Setup public DNS zone to point the domain address at the public VPS:

    acme-proxy.example. IN A
    acme-proxy.example. IN AAAA   2001:db8::1 IN CNAME  acme-proxy.example.
  3. On the public VPS, configure HTTP proxy to forward /.well-known/acme-challenge to PiKVM. For example in nginx:

    server {
       listen 80;
       listen [::]:80;
       location ^~ /.well-known/acme-challenge {
          proxy_set_header Host $host;
       location / {
          return 404;
  4. Now you can use kvmd-certbot certonly_webroot as in basic scenario above.