MS SQL Always-On Listener DNS entry lost in domain due to scavenging - should this be expected?

Brett

10/1/23, 2:40 PM

When running MS SQL with an Always-On group / listener, is it expected that the always-on listener DNS entry be kept active in the domain's DNS? When the listener was created, a DNS entry was added to AD DNS server with multiple IPs as part of the HA configuration.

The always-on listener DNS entry disappeared after some time, and logs indicate there was a scavenge that ran and cleaned up the record, considering it stale.

Is this expected, or is there some sort of mechanism in SQL Always-On that should keep the listener DNS alive? Or is there any other recommendation to keep the entry persisted in DNS? Or unexpected behaviour?

If the SQL server is restarted (OS) + always-on failovers, the DNS entry was automatically added back.

0 + 0

internal-dns

sql-server

alwayson

Ben Thul

10/1/23, 6:55 PM

Was the IP address assigned to the listener via DHCP? If so, I'd recommend against for this reason (as well another pretty big one which is "how long are you willing to wait for clients to reconnect *when* (not if) the listener gets a new IP?").

Brett

10/1/23, 7:13 PM

No, not DHCP. Static IPs were selected explicitly and used in the AG Listener setup. When the listener was set up, something in AG handled registering the hostname to DNS. The A record has 2 IPs, and the clients connecting to the listener have a parameter that handles active/passive of the listener, but it's always 2 static IPs.

Ben Thul

10/1/23, 8:00 PM

Got it. That "something" is Windows Clustering and it should maintain the virtual network name and the IPs that go along with that. I asked about DHCP because scavenging seems like it is intended to be used as a means to reclaim old DHCP-assigned addresses.

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: MS SQL Always-On Listener DNS entry lost in domain due to scavenging - should this be expected?

TH: รายการ MS SQL Always-On Listener DNS สูญหายในโดเมนเนื่องจากการไล่ออก - สิ่งนี้ควรคาดหวังหรือไม่

RO: Intrarea DNS MS SQL Always-On Listener pierdută în domeniu din cauza scavengingului - ar trebui să fie de așteptat?

RU: DNS-запись MS SQL Always-On Listener потеряна в домене из-за очистки — следует ли этого ожидать?

VI: Mục nhập DNS của trình nghe luôn bật MS SQL bị mất trong miền do nhặt rác - điều này có nên xảy ra không?

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