Replace a Designate Node

Problem

• One or more hosts authorized with the Designate role need to be decommissioned, shutdown, or otherwise replaced.
• If this has already occurred, one or more zones and their respective recordsets may be showing in either PENDING or ERROR state, depending on how long it's been.

Environment

• Platform9 Managed OpenStack - All Versions
• Designate

Procedure

1. Identify the IP address of your BIND server, and also of the Designate host(s) which are to remain or otherwise replace the old hosts.
2. Create a file update-masters.awk on the BIND server and populate it with the following content, modifying the bolded variables as per the legend below.

None

BEGIN {
SERVER_IP = "<BIND_IP>"
KEY = ""
MASTERS = "<DESIGNATE_NODE_1_IP> port 5354; <DESIGNATE_NODE_2_IP> port 5354;"
RNDC_ADD_CMD = "rndc -s %s addzone %s '%s'<br>"
RNDC_DEL_CMD = "rndc -s %s delzone %s<br>"
}

/^zone/ {
# Remove quotes from zone name
gsub("\"", "", $2)
zone_name = $2


# Iterate over remaining fields. Concatenate into 'zone_data'.
zone_data = ""
for(i=3; i<=NF; i++){
zone_data=zone_data" "$i
}
sub("^ ", "", zone_data)

# Find configured DNS servers
match(zone_data, /( ?([0-9]+.){4}( port [0-9]+);){1,}/, master_servers)
sub("^ ", "", master_servers[0])

# If configured masters do not match desired masters
if (master_servers[0] != MASTERS){
sub(master_servers[0], MASTERS, zone_data)

# Print command to delete zones
printf RNDC_DEL_CMD, SERVER_IP, zone_name

# Print command to add zones
printf RNDC_ADD_CMD, SERVER_IP, zone_name, zone_data
}
}

END {}

• SERVER_IP = IP on which the BIND server is listening.
• MASTERS = IP(s) of the aforementioned Designate host(s) which will remain to be online and become the active masters.

1. Execute the awk script and pipe the stdout to update_zones.sh.

None

# awk -f update-masters.awk /var/cache/bind/*.nzf ] update_zones.sh

1. Set the proper permissions and execute the resulting update_zones.sh script.

None

# chmod +x && ./update_zones.sh

Additional Info

Note: Afterward, it may take approximately 5-10 minutes for the DNS zones to update and reflect an ACTIVE status once again. If this does not occur, attempt to create a new DNS record or otherwise create an instance on a provider network or tenant network with a floating IP, either of which would automatically provision a DNS record (based on your Designate configuration). Once a new record is added, the zone and respective recordsets should show ACTIVE.