Bug 1966116: Corefile: Set bufsize to 512 bytes for all servers #276

sgreene570 · 2021-06-02T17:45:07Z

The CoreDNS bufsize plugin was enabled with a set size
of 1232 bytes in order to ensure that DNS queries bound for
an upstream resolver contain EDNS OPT Resource Records.
This resolved Bug 1949361.

Some DNS Clients, such as Go's built-in stub DNS resolver, are not
capable of handling DNS UDP messages that are larger than 512 bytes
(even if the proper EDNS flags are included in the message).
See golang/go#13561 &
golang/go#6464 accordingly.

This commit configures the bufsize plugin with a reduced bufsize of 512
bytes for all servers to ensure compatibility with primitive DNS
clients.

pkg/operator/controller/controller_dns_configmap.go:

Set bufsize to 512 bytes for all servers.

pkg/operator/controller/controller_dns_configmap_test.go:

Update unit test cases.

This commit is in support of Bug 196616 and should not cause
any regression from the changes merged as a part of Bug 1949361.

The CoreDNS bufsize plugin was enabled with a set size of 1232 bytes in order to ensure that DNS queries bound for an upstream resolver contain EDNS OPT Resource Records. This resolved Bug 1949361. Some DNS Clients, such as Go's built-in stub DNS resolver, are not capable of handling DNS UDP messages that are larger than 512 bytes (even if the proper EDNS flags are included in the message). See golang/go#13561 & golang/go#6464 accordingly. This commit configures the bufsize plugin with a reduced bufsize of 512 bytes for all servers to ensure compatibility with primitive DNS clients. pkg/operator/controller/controller_dns_configmap.go: Set bufsize to 512 bytes for all servers. pkg/operator/controller/controller_dns_configmap_test.go: Update unit test cases. This commit is in support of Bug 196616 and should not cause any regression from the changes merged as a part of Bug 1949361.

openshift-ci · 2021-06-02T17:45:15Z

@sgreene570: This pull request references Bugzilla bug 1966116, which is valid. The bug has been moved to the POST state. The bug has been updated to refer to the pull request using the external bug tracker.

3 validation(s) were run on this bug

bug is open, matching expected state (open)
bug target release (4.8.0) matches configured target release for branch (4.8.0)
bug is in the state ASSIGNED, which is one of the valid states (NEW, ASSIGNED, ON_DEV, POST, POST)

Requesting review from QA contact:
/cc @lihongan

In response to this:

Bug 1966116: Corefile: Set bufsize to 512 bytes for all servers

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Miciah · 2021-06-02T18:09:02Z

/lgtm

openshift-ci · 2021-06-02T18:09:21Z

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Miciah, sgreene570

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sgreene570 · 2021-06-02T18:42:39Z

/cherry-pick release-4.7

openshift-cherrypick-robot · 2021-06-02T18:42:40Z

@sgreene570: once the present PR merges, I will cherry-pick it on top of release-4.7 in a new PR and assign it to you.

In response to this:

/cherry-pick release-4.7

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openshift-bot · 2021-06-03T01:30:43Z

/retest