Bug 1236706

Hi Jake,

since etcd-2.0.11-2 ETCD_ADVERTISE_CLIENT_URLS is set to default value in /etc/etcd.conf.

Update to 7.1.4 will fix this issue.

Jan

This is definitely an unfortunate bug.   The only thing I can think to do here is to check on startup (via a patch in the code)
whether ETCD_LISTEN_CLIENT_URLS="http://localhost:2379" and is unset, then set the latter to "http://localhost:2379".

Jan, what do you think?

Colin,

I see. AH 7.1.3 release ships etcd-2.0.11-2 which sets ETCD_ADVERTISE_CLIENT_URLS="http://localhost:2379,http://localhost:4001".

As /etc/etcd/etcd.conf file is prefixed by %config(noreplace), it does not get replaced/updated when updating to AH 7.1.3. It has to be done manually on all machines with etcd installed.

Adding this line in etcd.service file in [service] section will fix the issue:
Environment="ETCD_ADVERTISE_CLIENT_URLS=http://localhost:2378"

[1] says "Settings from EnvironmentFile files override settings made with Environment=". So when there is no ETCD_ADVERTISE_CLIENT_URLS set in /etc/etcd/etcd.conf, the one defined in service file by Environment is taken. If ETCD_ADVERTISE_CLIENT_URLS is set in the config file, it overrides the one set in Environment.

[1] http://www.freedesktop.org/software/systemd/man/systemd.exec.html#EnvironmentFile=

Colin, can you verify?

Sorry, it is:

Environment="ETCD_ADVERTISE_CLIENT_URLS=http://localhost:2379"

Colin,

> This is definitely an unfortunate bug. The only thing I can think to do here
> is to check on startup (via a patch in the code)
> whether ETCD_LISTEN_CLIENT_URLS="http://localhost:2379" and is unset,
> then set the latter to "http://localhost:2379".

IINM, ETCD_LISTEN_CLIENT_URLS does not have to be set to "http://localhost:2379" only. 2379 and 4001 ports are preferred/allocated ports. However, there is nothing that stops administrator from using different ports for some reason.

What should be ETCD_ADVERTISE_CLIENT_URLS set to then? It is a good sign that etcd fails to start. If we decide to patch the source code/service file ETCD_ADVERTISE_CLIENT_URLS can be set to incorrect value. Then it will be more difficult to find out why etcd is not working as it is expected.

Besides in future other flags/envs can become mandatory and then patch etcd for each use case ... Would like to see this as an improvement of documentation to atomic host/etcd rather than patch etcd itself.

As Jake writes:
> Additional info:
> This appears to only be affecting Atomic Host, as on RHEL hosts it either
> works or drops an etcd.conf.rpmnew, whereas on AH there is no rpmnew file.

This seems to me as a bug in atomic host that is not providing rpmnew file.

This way or another update of etcd.conf is the correct fix, not patching/hacking etcd.

Created attachment 1049015 [details]
set ETCD_ADVERTISE_CLIENT_URLS to ETCD_LISTEN_CLIENT_URLS if empty

Colin,

the attached patch sets ETCD_ADVERTISE_CLIENT_URLS to ETCD_LISTEN_CLIENT_URLS if the former is empty. When a customer has ETCD_LISTEN_CLIENT_URLS set to different value then the default one he is responsible for setting ETCD_LISTEN_CLIENT_URLS to the correct value as well. So I don't think it is necessary to test for localhost infix.

Can you verify the patch?

Thanks
Jan

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://rhn.redhat.com/errata/RHBA-2015-1571.html

The needinfo request[s] on this closed bug have been removed as they have been unresolved for 1000 days