When we fetch the dns records by name, we get a list of records that match
the given name. As an optimization we look up to see if the new record we
want to create is already in the returned list to avoid performing any updates.
However, when the new record we want to create isn't in the returned list, it
is hard to say if the returned list contains the list of records that we want
to retain. For example, we might get a list of A records and we want to create
a CNAME record. Creating a new CNAME record without removing the A records is
a DNS misconfiguration. So to play safe we just remove all the existing records
in the list and create the new desired record.
**Note**: This is the opposite of what I said here - https://reviewable.kubernetes.io/reviews/kubernetes/kubernetes/44626#-Ki9xQOzybryHvsxNrra.
There can be multiple DNS resource records for a given name. They can
vary by type, ttl, rrdata and a number of various other parameters. It
is incorrect to return a single resource record for a given name.
This change updates the Get interface to return multiple records for a given
name and uses this list in the federated service controller to perform
DNS operations.
I went to look at the source comments, because the documentation is not exhaustive about what kind of DNS records are created for federated services (and http://blog.kubernetes.io/2016/07/cross-cluster-services.html is wrong...).
It turns out that even the comment is not in sync with the code: two out of three records listed use `.federation`, while the author probably meant `.mydomain.com` (which has less chance of getting mixed up with `myfed`). I fixed those, as well as a few spelling and parenthesis errors. Hopefully this will help others save time and not scratch their heads.
Automatic merge from submit-queue
error strings should not end with punctuation
**What this PR does / why we need it**:
Delete the end punctuation of error strings
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #
**Special notes for your reviewer**:
https://github.com/golang/go/wiki/CodeReviewComments#error-strings
**Release note**:
```release-note
```
Signed-off-by: yupeng <yu.peng36@zte.com.cn>
If we have a public & private zone with the same name (which is common
on AWS), this means we can still create records. Also tighten up some
of the logic to allow for zones with duplicate names.
We can put subdomains into hosted zones (for example,
foo.federation.example.com can be hosted in example.com)
By allowing sharing a common hosted zone, this means the user doesn't
have to do as much setup.
Without this you just get two pointers in the debug log.
Before:
I0627 21:48:44.136615 1 dns.go:215] Existing recordset {0xc820168830 0xc820691540} is not equal to needed recordset &{0xc820168848 0xc820686040}, removing existing and adding needed.
After:
I0627 22:26:46.221856 1 dns.go:215] Existing recordset <(clouddns) "federated-service.e2e-tests-service-cuza5.federation.svc.us-central1-c.us-central1.kube.5yetis.net." type=CNAME rrdatas=["federated-service.e2e-tests-service-cuza5.federation.svc.us-central1.kube.5yetis.net."] ttl=180>
I0627 22:26:46.221885 1 dns.go:216] ... not equal to needed recordset <(clouddns) "federated-service.e2e-tests-service-cuza5.federation.svc.us-central1-c.us-central1.kube.5yetis.net." type=CNAME rrdatas=["federated-service.e2e-tests-service-cuza5.federation.svc.us-central1.kube.5yetis.net."] ttl=180>
I0627 22:26:46.221919 1 dns.go:217] ... removing existing and adding needed.
