Workaround for systemd 242 assigning MAC addr for virtual devices #8351
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
|
Added the needs backport labels as all Cilium versions are affected. |
|
test-me-please |
|
test-me-please |
|
Bit surprised the veth pair isn't given a MAC already by whoever created it but OK. Patches LGTM. |
joestringer
approved these changes
Jun 19, 2019
There was a problem hiding this comment.
LGTM. Please also add a release note to the PR description to explain that this fixes compatibility with systemd 242.
(http://docs.cilium.io/en/latest/contributing/#submitting-a-pull-request step 9 if you need the formatting)
Also, do we need to do this for IPVLAN devices?
aanm
approved these changes
Jun 19, 2019
|
CI failed due to: Retrying. |
|
test-me-please |
|
ianvernon
approved these changes
Jun 19, 2019
|
@brb needs rebase. |
A generated MAC addr is unicast and locally administered. Signed-off-by: Martynas Pumputis <m@lambda.lt>
To include the change which allows to specify veth peer mac address (vishvananda/netlink#460). Signed-off-by: Martynas Pumputis <m@lambda.lt>
systemd 242+ tries to set a "persistent" MAC addr for any virtual device by default (controlled by MACAddressPolicy). As setting happens asynchronously after a device has been created, ep.Mac and ep.HostMac can become stale which has a serious consequence - the kernel will drop any packet sent to/from the endpoint. However, we can trick systemd by explicitly setting MAC addrs for both veth ends. This sets addr_assign_type for NET_ADDR_SET which prevents systemd from changing the addrs. Signed-off-by: Martynas Pumputis <m@lambda.lt>
To work around the systemd 242+ feature which tries to assign a persistent MAC address for any device by default (see commit message of the previous commit for more details). Signed-off-by: Martynas Pumputis <m@lambda.lt>
|
test-me-please |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This PR introduces a workaround for preventing the systemd 242+ from assigning MAC addrs for virtual devices after they have been created. The trick is to set a MAC addr when creating such device. This sets
addr_assign_typetoNET_ADDR_SETwhich makes the systemd to skip re-assigning of the MAC addr: https://github.com/systemd/systemd/blob/v242/src/udev/net/link-config.c#L292.Note that we don't apply the same trick to ipvlan slave devices, as they inherit a MAC addr from their master, so they bypass the issue.
See #8304 for more details about the systemd feature and what it causes to Cilium.
Fix #8304.
This change is