Cause: A value of 16000 nodes was set when calculating the end of DHCP allocation pool when provisioning the nodes subnet.
Consequence: deploying OpenShift on OpenStack platform with a machine CIDR smaller than /18 resulted in an error.
Fix: stop hardcoding the number of nodes and instead dynamically calculate the end of DHCP allocation pool.
Result: it is now possible to deploy OpenShift on OpenStack with machine CIDR of any length, provided it is large enough to for all needed nodes.
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory (OpenShift Container Platform 4.5.11 bug fix update), and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.
https://access.redhat.com/errata/RHBA-2020:3719
Verified on 4.5.0-0.nightly-2020-09-14-030924 [core@mrnd-13-45-rm5j6-bootstrap ~]$ ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: ens3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1450 qdisc fq_codel state UP group default qlen 1000 link/ether fa:16:3e:b4:33:16 brd ff:ff:ff:ff:ff:ff inet 192.168.0.123/24 brd 192.168.0.255 scope global dynamic noprefixroute ens3 valid_lft 86194sec preferred_lft 86194sec inet 192.168.0.6/24 scope global secondary ens3 valid_lft forever preferred_lft forever inet 192.168.0.5/24 scope global secondary ens3 valid_lft forever preferred_lft forever inet6 fe80::242e:3a21:c812:5b31/64 scope link noprefixroute valid_lft forever preferred_lft forever [core@mrnd-13-45-rm5j6-bootstrap ~]$