Due to changes in nss-tools package pcs is now unable to setup new qnetd and add it to a cluster. This is partially caused by issues in corosync-qnetd-certutil which pcs uses, partially by pcs itself as it hard-codes "cert8.db" filename in a few places.

# rpm -q corosync-qnetd
corosync-qnetd-2.91.0-1.fc29.x86_64
# rpm -q corosync-qdevice
corosync-qdevice-2.91.0-1.fc29.x86_64
# rpm -q nss-tools
nss-tools-3.37.3-3.fc29.x86_64

[root@fed28-node3:~]# pcs qdevice setup model net
Quorum device 'net' initialized

[root@fed28-node1:~]# pcs quorum device add model net host=fed28-node3 algorithm=ffsplit 
Setting up qdevice certificates on nodes...
Error: fed28-node1: Error: Unable to initialize quorum device 'net': password file contains no data
Invalid password.
certutil: Could not set password for the slot: SEC_ERROR_INVALID_ARGS: security library: invalid arguments.
chown: cannot access '/etc/corosync/qdevice/net/nssdb/key3.db': No such file or directory
chown: cannot access '/etc/corosync/qdevice/net/nssdb/cert8.db': No such file or directory
chown: cannot access '/etc/corosync/qdevice/net/nssdb/secmod.db': No such file or directory
chmod: cannot access '/etc/corosync/qdevice/net/nssdb/key3.db': No such file or directory
chmod: cannot access '/etc/corosync/qdevice/net/nssdb/cert8.db': No such file or directory
chmod: cannot access '/etc/corosync/qdevice/net/nssdb/secmod.db': No such file or directory
certutil: could not decode certificate: SEC_ERROR_REUSED_ISSUER_AND_SERIAL: You are attempting to import a cert with the same issuer/serial as an existing cert, but that is not the same cert.
Creating new key and cert db
Using existing noise file /etc/corosync/qdevice/net/nssdb/noise.txt
Importing CA, use --skip-offline to override
Error: fed28-node2: Error: Unable to initialize quorum device 'net': password file contains no data
Invalid password.
certutil: Could not set password for the slot: SEC_ERROR_INVALID_ARGS: security library: invalid arguments.
chown: cannot access '/etc/corosync/qdevice/net/nssdb/key3.db': No such file or directory
chown: cannot access '/etc/corosync/qdevice/net/nssdb/cert8.db': No such file or directory
chown: cannot access '/etc/corosync/qdevice/net/nssdb/secmod.db': No such file or directory
chmod: cannot access '/etc/corosync/qdevice/net/nssdb/key3.db': No such file or directory
chmod: cannot access '/etc/corosync/qdevice/net/nssdb/cert8.db': No such file or directory
chmod: cannot access '/etc/corosync/qdevice/net/nssdb/secmod.db': No such file or directory
certutil: could not decode certificate: SEC_ERROR_REUSED_ISSUER_AND_SERIAL: You are attempting to import a cert with the same issuer/serial as an existing cert, but that is not the same cert.
Creating new key and cert db
Using existing noise file /etc/corosync/qdevice/net/nssdb/noise.txt
Importing CA, use --skip-offline to override
Error: Errors have occurred, therefore pcs is unable to continue

[root@fed28-node3:~]# pcs qdevice destroy net
Stopping quorum device...
quorum device stopped
quorum device disabled
Quorum device 'net' configuration files removed
[root@fed28-node3:~]# pcs qdevice setup model net
Error: Quorum device 'net' has been already initialized