Cockpit usually requires that web browsers communicate with it using HTTPS, for security reasons.

HTTPS Requirement

Cockpit listens for both HTTP and HTTPS connections on the same port, by default 9090. If an HTTP connection is made, Cockpit will redirect that connection to HTTPS. There are some exceptions:

  • If an HTTP connection comes from +localhost+ (+127.0.0.1+ or +::1+, then Cockpit will allow communication without redirecting to HTTPS.

  • Certain URLs, like +/ping+ are not required to use HTTPS.

This behavior can be overridden by setting the +AllowUnencrypted+ option in +cockpit.conf+.

Certificates

Cockpit will load a certificate from the +/etc/cockpit/ws-certs.d+, directory, or below +$XDG_CONFIG_DIRS+ if set (see cockpit.conf). It will use the last file with a +.cert+ or +.crt+ extension in alphabetical order. The file should contain one or more OpenSSL style +BEGIN CERTIFICATE+ blocks for the server certificate and the intermediate certificate authorities.

The private key must be contained in a separate file with the same name as the certificate, but with a +.key+ suffix instead. The key must not be encrypted.

If no certificate is found, a self-signed certificate is created and stored in the +0-self-signed.cert+ file. On some platforms, Cockpit will also generate a ca.crt in that directory, which may be safely imported into client browsers.

Cockpit will read the files as root, so they can have tight permissions.

To check which certificate +cockpit-ws+ will use run the following command.

$ sudo /usr/libexec/cockpit-certificate-ensure --check

Or, on Debian-based systems:

$ sudo /usr/lib/cockpit/cockpit-certificate-ensure --check

If using +certmonger+ to manage certificates, following command can be used to automatically prepare a certificate/key file pair:

getcert request -f /etc/cockpit/ws-certs.d/50-certmonger.cert \
                -k /etc/cockpit/ws-certs.d/50-certmonger.key \
                -D myhostname.example.com \
                [--ca=...]

This will not work on Red Hat Enterprise Linux 8 by default. Adjust the SELinux type of the certificate directory to +cert_t+ to allow certmonger to write its certificates there:

semanage fcontext -a -t cert_t '/etc/cockpit/ws-certs\.d(/.*)?'
restorecon -v /etc/cockpit/ws-certs.d