Re: Kickstart / PXE / Cobbler / Ansible
Hi Benjamin, Benjamin Lefoul writes: > Hi all, > > I am actually interested in the automated install topic (currently > taking place in the other discussion, but I don't want to feed the > troll so I'll start a new one). > > Someone just mentioned Cobbler, and the fact that it's RH's baby. Is > this in any way linked to the recent acquisition of Ansible ? In > fact, I never really understood what Ansible was, and does it have its > place in automated install? Can it replace Kickstart? > > As you can see I am pretty naive about the topic... I don't know very much about kickstart but am currently using ansible to set up two administration servers for a test cluster. My meagre understanding is that kickstart is mainly aimed at the initial lower-level installation (partitioning the disk, installing the base OS and other packages, ...). Ansible on the other hand requires the machines you are managing to be already up and running and, normally, accessible via ssh. Thus it seems it is a more fancy way of doing what kickstart can probably do in the post-install section. However, Ansible works with 'playbooks', which are sets of 'plays', which in turn are sets of tasks to be carried out on a set of hosts. You can run entire playbooks or just groups of tasks and you can also define roles, such as 'ldapserver' or 'dbserver' to bundle associated tasks together. In general it seems slightly more orientated towards automated day-to-day management of multiple, heterogeneous hosts. That having been said, I am no expert. Regards Loris -- Dr. Loris Bennett (Mr.) ZEDAT, Freie Universität Berlin Email loris.benn...@fu-berlin.de
Setting hostname
Hi, I'm using ansible to set up two servers and have run into the problem that on one server 'hostname' returns the just the name of the machine, but on the other I get the FQDN: # hostname -s; hostname -d; hostname -f; hostname tadmin01 test.cluster tadmin01.test.cluster tadmin01 # hostname -s; hostname -d; hostname -f; hostname tadmin02 test.cluster tadmin02.test.cluster tadmin02.test.cluster The following files are identical on both servers /etc/hosts /etc/resolv.conf The files /etc/sysconfig/network differs just in the following way: < HOSTNAME=tadmin01 --- > HOSTNAME=tadmin02 What other files could have an influence on what 'hostname' returns? Cheers, Loris -- This signature is currently under construction.
Re: Setting hostname
Hi Benjamin, Benjamin Lefoul writes: > Hi Loris, > > On SL7, I believe hostnames are best set declaratively in the file > /etc/hostname (as has been the case for long on other distros). I > suspect the preferred imperative way to set hostname is with > "hostnamectl set-hostname" (check the man hostnamectl). > > Regards, > > Benjamin Lefoul > nWISE AB [snip (50 lines)] Ah, I should have said: I'm on SL 6.7 and 'hostnamectl' doesn't seem to be available. Cheers, Loris -- This signature is currently under construction.
Re: Setting hostname
Hi Paddy,
Paddy Doyle writes:
> Hi Loris,
>
> On Tue, Mar 15, 2016 at 11:43:55AM +0100, Loris Bennett wrote:
>
>> Hi,
>>
>> I'm using ansible to set up two servers and have run into the problem
>> that on one server 'hostname' returns the just the name of the machine,
>> but on the other I get the FQDN:
>>
>> # hostname -s; hostname -d; hostname -f; hostname
>> tadmin01
>> test.cluster
>> tadmin01.test.cluster
>> tadmin01
>>
>> # hostname -s; hostname -d; hostname -f; hostname
>> tadmin02
>> test.cluster
>> tadmin02.test.cluster
>> tadmin02.test.cluster
>>
>> The following files are identical on both servers
>>
>> /etc/hosts
>> /etc/resolv.conf
>>
>> The files
>>
>> /etc/sysconfig/network
>>
>> differs just in the following way:
>>
>> < HOSTNAME=tadmin01
>> ---
>> > HOSTNAME=tadmin02
>>
>> What other files could have an influence on what 'hostname' returns?
>
> Is caching an issue? E.g. with sssd or nscd? That gave us some trouble with
> ansible iirc.
I also suspected something might be being cached, but I have restarted
all the services I thought might play a role and the difference remains.
> We ended up using an explicit ansible rule to set the FQDN in
> /etc/sysconfig/network just to make sure that every node was consistent. And
> then if necessary use "hostname -s" or "hostname -f" as required.
The problem is that I am setting up DRDB with the following resource
definition:
resource r0 {
net {
protocol C;
allow-two-primaries yes;
}
on tadmin01 {
device /dev/drbd0;
disk /dev/sda1;
address 10.141.235.254:7789;
meta-disk internal;
}
on tadmin02 {
device /dev/drbd0;
disk /dev/sda1;
address 10.141.235.253:7789;
meta-disk internal;
}
}
However, when I do
drbdadm create-md r0
I get the error
'r0' not defined in your config (for this host).
>From my googling my understanding is that the entry in the DRDB config
must match the result returned by 'hostname'. I can obviously just
tweak the DRDB config to make it work, but I would really like to
understand why 'hostname' without any options gives me the FQDN in one
case and not in the other
Cheers,
Loris
--
This signature is currently under construction.
Re: Setting hostname
Hi Nico, Nico Kadel-Garcia writes: [snip (27 lines)] > "system-config-network-tui" works pretty well if installed. I've had a look at the settings with this, and the setting are as I expect. > The problem is that the $HOSTNAME for the system isn't published in > DNS, nor is it the first hostname for a line in /etc/hosts, so the > "hostname --fqdn" is not finding it associated with your IP addresses. I may have explained it badly, but 'hostname --fqdn' works as expected: [root@tadmin01 ~]# hostname -f tadmin01.test.cluster [root@tadmin02 ~]# hostname -f tadmin02.test.cluster The difference is when I call 'hostname' *without* any option: [root@tadmin01 ~]# hostname tadmin01 [root@tadmin02 ~]# hostname tadmin02.test.cluster > The usual approach for portable laptops is to put a line like this in > /etc/hosts somewhere. > > 127.0.0.1 mymachine.mydomain > > Do *not* put this. > > 127.0.0.1 mymachine mymachine.mydomain > > And do not touch the line for localhost, the way some installers do. > > 127.0.0.1 localhost.localdomain localhost localhost4.localdomain > localhost4 mymachine.mydomain mymachine > > That last one is very common with a lot of bad, bad, software > installers and configuration tools. Use a *different line* for the > FQDN. > > Note that some software also may work better if you have the hostname > tied to the systems's live IP addresses, but that's usually because > it's bad software. /etc/host looks like this (except with real external IP addresses) on both machines: 127.0.0.1 localhost.localdomain localhost ::1 localhost6.localdomain6 localhost6 xxx.xxx.xxx.xxx tadmin01.zedat.fu-berlin.de xxx.xxx.xxx.xxx tadmin02.zedat.fu-berlin.de 10.141.235.254 tadmin01.test.cluster tadmin01 10.141.235.253 tadmin02.test.cluster tadmin02 But as they are identical, it shouldn't be the source of the difference. Cheers, Loris -- This signature is currently under construction.
Re: Setting hostname
Hi Andrew, Andrew C Aitchison writes: > On Tue, 15 Mar 2016, Loris Bennett wrote: > >> Hi, >> >> I'm using ansible to set up two servers and have run into the problem >> that on one server 'hostname' returns the just the name of the machine, >> but on the other I get the FQDN: >> >> # hostname -s; hostname -d; hostname -f; hostname >> tadmin01 >> test.cluster >> tadmin01.test.cluster >> tadmin01 >> >> # hostname -s; hostname -d; hostname -f; hostname >> tadmin02 >> test.cluster >> tadmin02.test.cluster >> tadmin02.test.cluster > > Does > type hostname > give the same result on both machines ? Yes, in both cases I get # type hostname hostname is /bin/hostname >> The following files are identical on both servers >> >> /etc/hosts >> /etc/resolv.conf >> >> The files >> >> /etc/sysconfig/network > ... ... >> What other files could have an influence on what 'hostname' returns? > > "man hostname" suggests a few more files that could be relevant. OK, I've checked /etc/nsswitch.conf /etc/hosts /etc/host.conf all those and there are no differences. /etc/sysconfig/network differ only by < HOSTNAME=tadmin01 --- > HOSTNAME=tadmin02 So I'm still confused. Cheers, Loris -- This signature is currently under construction.
Re: Setting hostname
Tom H writes: > On Wed, Mar 16, 2016 at 1:53 PM, Loris Bennett > wrote: >> Tom H writes: >>> On Tue, Mar 15, 2016 at 1:42 PM, Nico Kadel-Garcia wrote: >>>> On Tue, Mar 15, 2016 at 8:32 AM, Nico Kadel-Garcia >>>> wrote: >>>> >>>>> The problem is that the $HOSTNAME for the system isn't published in >>>>> DNS, nor is it the first hostname for a line in /etc/hosts, so the >>>>> "hostname --fqdn" is not finding it associated with your IP addresses. >>>>> The usual approach for portable laptops is to put a line like this in >>>>> /etc/hosts somewhere. >>>>> >>>>> 127.0.0.1 mymachine.mydomain >>> >>> On SL6, I've adopted the Debian approach: >>> >>> # cat /etc/hosts >>> 127.0.0.1 localhost >>> 127.0.1.1 tadmin.test.cluster tadmin >>> >>> # cat /etc/sysconfig/network >>> NETWORKING=yes >>> HOSTNAME=tadmin >>> >>> # hostname >>> tadmin >>> >>> # hostname -s >>> tadmin >>> >>> # hostname -f >>> tadmin.test.cluster >>> >>> # hostname -d >>> test.cluster >> >> This is what my set-up looks like, too. > > It can't be because then (1) "/etc/hosts" would differ on tadmin01 and > tadmin02 and (2) "hostname" on tadmin02 would return "tadmin02". I meant that my set-up is the same in that I have similar data in those two files. This is what /etc/hosts looks like: [root@tadmin01 etc]# cat /etc/hosts 127.0.0.1 localhost.localdomain localhost ::1 localhost6.localdomain6 localhost6 xxx.xxx.xxx.xxx tadmin01.zedat.fu-berlin.de xxx.xxx.xxx.xxx tadmin02.zedat.fu-berlin.de 10.141.235.254 tadmin01.test.cluster tadmin01 10.141.235.253 tadmin02.test.cluster tadmin02 It is the same on tadmin01 and tadmin02. And for /etc/sysconfig/network on tadmin01 I have [root@tadmin01 ~]# cat /etc/sysconfig/network # Generated from an ansible template NETWORKING=yes NETWORKING_IPV6=no HOSTNAME=tadmin01 GATEWAY=xxx.xxx.xxx.xxx and on tadmin02 [root@tadmin02 ~]# cat /etc/sysconfig/network # Generated from an ansible template NETWORKING=yes NETWORKING_IPV6=no HOSTNAME=tadmin02 GATEWAY=xxx.xxx.xxx.xxx [snip (64 lines)] I still get [root@tadmin01 ~]# hostname tadmin01 and [root@tadmin02 ~]# hostname tadmin02.test.cluster Cheers, Loris -- This signature is currently under construction.
Re: Setting hostname
Tom H writes: > On Tue, Mar 15, 2016 at 1:42 PM, Nico Kadel-Garcia wrote: >> On Tue, Mar 15, 2016 at 8:32 AM, Nico Kadel-Garcia wrote: >> >>> The problem is that the $HOSTNAME for the system isn't published in >>> DNS, nor is it the first hostname for a line in /etc/hosts, so the >>> "hostname --fqdn" is not finding it associated with your IP addresses. >>> The usual approach for portable laptops is to put a line like this in >>> /etc/hosts somewhere. >>> >>> 127.0.0.1 mymachine.mydomain > > On SL6, I've adopted the Debian approach: > > # cat /etc/hosts > 127.0.0.1 localhost > 127.0.1.1 tadmin.test.cluster tadmin > > # cat /etc/sysconfig/network > NETWORKING=yes > HOSTNAME=tadmin > > # hostname > tadmin > > # hostname -s > tadmin > > # hostname -f > tadmin.test.cluster > > # hostname -d > test.cluster This is what my set-up looks like, too. > On SL7, libnss_myhostname does the job of the second "/etc/hosts" line > (but with 127.0.0.2) automatically. > > To the OP: > > Where are you setting the domainname? # cat /etc/sysconfig/network-scripts/ifcfg-eth0 DEVICE=eth0 ONBOOT=yes BOOTPROTO=none IPADDR=10.141.235.253 NETMASK=255.255.0.0 DOMAIN=test.cluster USERCTL=no Cheers, Loris -- This signature is currently under construction.
Re: Setting hostname
Brandon Vincent writes: > On Mar 16, 2016 7:56 AM, "Loris Bennett" > wrote: >> >> Brandon Vincent writes: >> >> > On Mar 15, 2016 3:44 AM, "Loris Bennett" >> > wrote: >> >> What other files could have an influence on what 'hostname' returns? >> > >> > Could you post the output of >> > >> > getent hosts [hostname] and getent hosts [ip] for both systems? >> > >> > Also please post the hosts line from nsswitch.conf from both machines. >> > >> > Brandon Vincent >> > >> >> [root@tadmin01 ~]# getent hosts tadmin01 >> 10.141.235.254 tadmin01.test.cluster tadmin01 >> [root@tadmin01 ~]# getent hosts 10.141.235.254 >> 10.141.235.254 tadmin01.test.cluster tadmin01 >> >> [root@tadmin02 ~]# getent hosts tadmin02 >> 10.141.235.253 tadmin02.test.cluster tadmin02 >> [root@tadmin02 ~]# getent hosts 10.141.235.253 >> 10.141.235.253 tadmin02.test.cluster tadmin02 >> >> [root@tadmin01 ~]# grep hosts /etc/nsswitch.conf >> #hosts: db files nisplus nis dns >> hosts: files dns >> >> [root@tadmin02 ~]# grep hosts /etc/nsswitch.conf >> #hosts: db files nisplus nis dns >> hosts: files dns >> >> Cheers, >> >> Loris >> >> -- >> Dr. Loris Bennett (Mr.) >> ZEDAT, Freie Universität Berlin Email loris.benn...@fu-berlin.de > > Looks good. Verify there is no /etc/hostname on the system (or if there is, > ensure the contents are correct. > > Are you using NetworkManager or the traditional network service? > > These IPs are static, right? Not assigned by DHCP but entered manually. > > Brandon Vincent OK, sorry for wasting everyone's time. I rebooted tadmin02 and now I get [root@tadmin02 ~]# hostname tadmin02 as expected. I assume I must have done hostname tadmin.test.cluster at some point. Which begs the question: Is there any way to tell that the hostname has been set via hostname some.random.address rather via some init script reading /etc/sysconfig/network? Thanks for all the help, Loris -- This signature is currently under construction.
Re: Setting hostname
Brandon Vincent writes: > On Mar 15, 2016 3:44 AM, "Loris Bennett" > wrote: >> What other files could have an influence on what 'hostname' returns? > > Could you post the output of > > getent hosts [hostname] and getent hosts [ip] for both systems? > > Also please post the hosts line from nsswitch.conf from both machines. > > Brandon Vincent > [root@tadmin01 ~]# getent hosts tadmin01 10.141.235.254 tadmin01.test.cluster tadmin01 [root@tadmin01 ~]# getent hosts 10.141.235.254 10.141.235.254 tadmin01.test.cluster tadmin01 [root@tadmin02 ~]# getent hosts tadmin02 10.141.235.253 tadmin02.test.cluster tadmin02 [root@tadmin02 ~]# getent hosts 10.141.235.253 10.141.235.253 tadmin02.test.cluster tadmin02 [root@tadmin01 ~]# grep hosts /etc/nsswitch.conf #hosts: db files nisplus nis dns hosts: files dns [root@tadmin02 ~]# grep hosts /etc/nsswitch.conf #hosts: db files nisplus nis dns hosts: files dns Cheers, Loris -- Dr. Loris Bennett (Mr.) ZEDAT, Freie Universität Berlin Email loris.benn...@fu-berlin.de
