[Freeipa-devel] [PATCH] 888 always verify hostname

[Rob Crittenden]

Martin Kosek wrote:
> On Thu, 2011-10-06 at 22:59 -0400, Rob Crittenden wrote:
>> When installing with DNS we skip a few hostname checks on the assumption
>> that the DNS we are installing will cover things. We still need to
>> verify /etc/hosts and we do this with gethostbyname_ex() which returns
>> the primary name and all other names of the host. If the primary name
>> doesn't match (e.g. the shortname is defined first in /etc/hosts) or it
>> isn't resolvable at all then we error out.
>>
>> This also prevents a chicken-and-egg error as several services need to
>> start before DNS is available so the hostname must be defined.
>>
>> rob
>
> I see several problems with the patch. At first, it needs a rebase, I
> reworked the exceptions raised in verify_fqdn in #1899.
>
> Then, this patch would break several things:
>
> 1) Now, when we install a server with --setup-dns and the host is not
> resolvable, we add a record to /etc/hosts ourselves, so that the user is
> not obliged to hack /etc/hosts:
>
> # ipa-server-install --setup-dns
> ...
> Server host name [vm-050.idm.lab.bos.redhat.com]:
>
> Warning: skipping DNS resolution of host vm-050.idm.lab.bos.redhat.com
> The domain name has been calculated based on the host name.
>
> Please confirm the domain name [idm.lab.bos.redhat.com]:
>
> Unable to resolve IP address for host name
> Please provide the IP address to be used for this host name: 10.16.78.50
> Adding [10.16.78.50 vm-050.idm.lab.bos.redhat.com] to your /etc/hosts file<<<<<<
> The IPA Master Server will be configured with
> Hostname:    vm-050.idm.lab.bos.redhat.com
> IP address:  10.16.78.50
> Domain name: idm.lab.bos.redhat.com

Yes but the entry is added /etc/hosts at the very END of installation, 
apparently too late for some things. We can alternately add this prior 
to configuring anything else.

>
>
> 2) This will break ipa-replica-prepare. We cannot assume that only local
> host names are passed to to verify_fqdn since it is also used to for new
> replica hostname check in ipa-replica-prepare:
>
> # ipa-replica-prepare vm-103.idm.lab.bos.redhat.com
> Directory Manager (existing master) password:
>
> The host name vm-103.idm.lab.bos.redhat.com is not resolvable. It must
> appear in at least /etc/hosts.
> Add the --ip-address argument to create a DNS entry.
>
> We must be very cautious in this function, there was already a BZ from
> RHEV-M guys which could be now broken:
>
> https://bugzilla.redhat.com/show_bug.cgi?id=729357
>
> Martin
>

Ok, perhaps it just needs to be pulled directly into ipa-server-install. 
We do need some mechanism to check /etc/hosts to be sure that there 
isn't an existing bad host entry.

rob