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On Linode, external-dns is creating CNAME alias and no TXT/A Records when target is Load Balancer #2499
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Having chatted with @jpetazzo (creator of Linode's tutorial mentioned above), it does look like the reason might be because of external-dns's logic to create a CNAME if the target looks like an ELB. Setting the --txt-prefix flag, as per #262, gets around the issue of the TXT not being created. I believe that the logic of detecting an ELB should be changed. If the LoadBalancer has an IP address and not a domain name, this logic/change from A Record to CNAME does not seem necessary. Furthermore, applying the |
I think I'm hitting a similar issue after upgrading my LKE cluster from 1.20 to 1.22. I'm using traefik When I enable debug logs I see:
Note the empty I noticed the new domain on my new nodebalancer and eventually found https://www.linode.com/blog/linode/notice-changes-to-members-linode-com-and-nodebalancer-linode-com/ -- My cluster had been up for over a year so I hadn't noticed earlier. Seems like it could be related. Prior to this I'd run into #961 -- I've verified the RBAC rules appear to be correct, and |
same behaviour for me than @peedrr described it.. |
For me too, same behaviour than @peedrr described it. |
Is there an annotation to force an A record rather than a CNAME record? You can't use a CNAME at the base of a domain and external-dns has no way to know if a record will be the base or not. A user hint seems the only way out. |
I hope I'm not muddying the waters in case my issues are unrelated, but I'm not seeing that it's a unique issue just yet. In my case, I'm running traefik ingress, with these
In case its relevant, the service is also configured with:
Before upgrading my clusters (1.20)/nodebalancer, Runtime configs:
... passing
At least in my case I never intended to create a
Not that I could find: https://github.com/kubernetes-sigs/external-dns/blob/master/source/source.go#L40 |
The root of this issue, as mentioned before, is that you need to add a prefix or suffix to the TXT record so that it has a unique hostname. In the official Helm chart, this is accomplished via something like: spec:
values:
registry: txt
txtOwnerId: ""
txtPrefix: ""
txtSuffix: "_externaldns" After hitting the issue described, the above fixed my issues on LKE 1.22 (for services, at least -- haven't tested with ingress like @mars64 was mentioning). The same principals from the AWS FAQ entry you mentioned apply. More discussion is also in this StackOverflow. I do agree that the auto-detection logic should probably be changed, though. |
After looking into this more, the behavior has definitely changed since the rollout of the new subdomain for nodebalancers. Using Now, a target like Previously, the Go playground to demonstrate it. Really weird behavior. Still looking more into it, but hopefully this clarifies why it's happening. EDIT: it's because string comparisons like greater/less than compare alphabetically (lexicographically). Since |
Indeed. This seems like behavior that should be configurable (to choose the service IP or choose the hostname (CNAME)). |
I think this might be related. I've recently found that when adding the service.beta.kubernetes.io.do-loadbalancer-hostname annotation to external-dns's service, it causes external-dns to create CNAMEs rather than A records. Perhaps that because this setting replaces status.LoadBalancer.ingress.ip="1.2.3.4" with status.LoadBalancer.ingress.hostname="example.com" and it doesn't have an IP address to which to point A records. That's a digitalocean specific setting, but I suspect there are equivalents for other providers? Is that behavior expected, and likely an unavoidable consequence? |
What happened:
What you expected to happen:
A & TXT Records created, as per Linode's tutorial video which uses the same commands (below)
How to reproduce it (as minimally and precisely as possible):
(Assumes existing access to Linode, Linode API key and Bitnami helm repo, with mydomain.com managed by Linode DNS)
Anything else we need to know?:
Not sure if this is related, but I saw in FAQs that external-dns creates CNAME "when target looks like an ELB" on AWS. The FAQ then gives AWS-specific solution which obviously doesn't work on Linode. Maybe something similar is happening here?
Environment:
external-dns --version
): 0.10.2The text was updated successfully, but these errors were encountered: