[SR-Users] Kamailio IMS as kubernetes pods

Thu Aug 27 15:52:51 CEST 2020

Hi David,

Yes that is right, so when you set to ClusterIP:none, it turns the services
into a headless services. and the DNS will resolve to a single POD, instead
of a group of PODs, and you can reach every POD through the DNS. IPs may
change but the DNS will stay fixed when you use Statefullset, as you need a
fixed DNS name for the pod. If you  use Deployment you get a randomly
generated name, which is not what you want.

Abdirahman

On Thu, 27 Aug 2020 at 08:06, David Villasmil <
david.villasmil.work at gmail.com> wrote:

> Hello Abdirahman,
>
> Thanks for replying.
>
> Do you mean if I create a service for the label selector of what’s running
> in the pod, but ser ClusterIP: None, when another pod tries to resolve that
> service, it will get the actual IP of the running POD?
>
>
> On Wed, 26 Aug 2020 at 18:02, Abdirahman A. Osman <
> abdirahman.osm at gmail.com> wrote:
>
>> Hi Pavithra,
>>
>> Since POD IPs change, you have to rely on DNS records. To have a fixed
>> DNS name like
>>
>> kamailio.kamalio-service.namespace.svc.cluster.local
>>
>>
>>
>> for a pod you will have to use StatefullSet, so the pod DNS name doesn't
>> change. Also you have to use Services and set it to ClusterIP: none, it
>> will turn your pods to headless services and no load balancing is involved.
>> and from my understanding you will be able to reach each POD directly
>> through the DNS name.
>> https://kubernetes.io/docs/concepts/services-networking/service/
>>
>> and don't forget to set  your /etc/resolv.conf with the kubedns IP
>> address.
>>
>> Abdirahman
>>
>>
>>
>> On Wed, 26 Aug 2020 at 12:45, Pavithra Mohanraja <pavimohan3004 at gmail.com>
>> wrote:
>>
>>> Hi Abdirahman,
>>>
>>> Do you mean , if I set clusterIP as None, then kubedns server will be
>>> pointing to pod ip so that kubedns/coredns will use pod ip for pod
>>> communication instead of service IP.
>>>
>>>
>>> Is my understanding correct? From your explanation.
>>>
>>> If this is the case, pod ip will be changing whenever I launch the pods
>>> . How that can be resolved.
>>>
>>> Could you kindly helo me with this?
>>>
>>>
>>> Thanks,
>>> Pavithra
>>>
>>> On Wed, Aug 26, 2020, 9:26 PM Abdirahman A. Osman <
>>> abdirahman.osm at gmail.com> wrote:
>>>
>>>> David,
>>>>
>>>>
>>>>
>>>> Assuming those are pod ips. Using services doesn’t work
>>>>>
>>>>> since the dns name will resolve to a k8s service ip and no the actual
>>>>>
>>>>> pod running the service.
>>>>>
>>>>
>>>> If you set   *clusterIP: None* in the services, you will get POD IP.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Abdirahman
>>>>
>>>>
>>>>
>>>> On Wed, 26 Aug 2020 at 10:48, Pavithra Mohanraja <
>>>> pavimohan3004 at gmail.com> wrote:
>>>>
>>>>> Hi,
>>>>> Thanks for the answers.
>>>>> @David has got my question.
>>>>>
>>>>> I have a seperate dns server running in my pcscf pod . So in my
>>>>> /etc/resolv.conf file , I would be configuring
>>>>> nameserver <pcscf pod ip>
>>>>> in all other cscf pods as well for communication.
>>>>>
>>>>>
>>>>>
>>>>> My question here is how to change the dns server pointing to cluster
>>>>> ip so that my domain name for IMS will be pointing to coredns itself. It
>>>>> will restrict me from using pod IP since it changes everytime.
>>>>>
>>>>>
>>>>> @David, can you please tell me the last two lines briefly. I did not
>>>>> get it.how you configured . You mean to say still you are using pod Ip.
>>>>>
>>>>>
>>>>> On Wed, Aug 26, 2020, 8:02 PM David Villasmil <
>>>>> david.villasmil.work at gmail.com> wrote:
>>>>>
>>>>>> I’ve been trying to figure this out as well.
>>>>>> I haven’t yet found a way of publishing to kube-dns the pod IP of the
>>>>>> running service.
>>>>>>
>>>>>> I.e.:
>>>>>> kamailio.whatever.local on ip 10.0.0.1
>>>>>> Rtpengine.whatever.local on ip 10.0.0.2
>>>>>> Appserver.whatever.local on 10.0.0.3
>>>>>>
>>>>>> Assuming those are pod ips. Using services doesn’t work since the dns
>>>>>> name will resolve to a k8s service ip and no the actual pod running the
>>>>>> service.
>>>>>>
>>>>>> Assigning IPs hardcoded doesn’t work either since it might change if
>>>>>> the docker changes pod. I can have multiple modes on which a service can
>>>>>> run, but only one service (kamailio, rtpengine, appserver, etc) will run on
>>>>>> a given pod.
>>>>>>
>>>>>> On Wed, 26 Aug 2020 at 15:18, Abdirahman A. Osman <
>>>>>> abdirahman.osm at gmail.com> wrote:
>>>>>>
>>>>>>> Hi
>>>>>>>
>>>>>>> Pavithra
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> You can use the kubedns/CoreDNS of the kubernetes cluster to resolve
>>>>>>> Internal DNS records of the pods.To assign DNS records for each POD you
>>>>>>> have to deploy a service and set the ClusterIP: none. and the dns record
>>>>>>> will be something like kamailio.kamalio-service.platform.svc.cluster.local
>>>>>>> which is the podname.servicename.namespace.svc.cluster.local
>>>>>>>
>>>>>>> In the resolve.conf you will put the kubeDNS/CoreDNS IP as the
>>>>>>> nameserver.  You can set this in the kubernetes manifest file
>>>>>>>
>>>>>>>       dnsPolicy: "None"
>>>>>>>       dnsConfig:
>>>>>>>         nameservers:
>>>>>>>           - 10.34.0.1 (
>>>>>>>
>>>>>>> kubeDNS/CoreDNS )
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> Abdirahman
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> On Tue, 25 Aug 2020 at 15:34, Sergey Safarov <s.safarov at gmail.com>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> I am not k8s developer.
>>>>>>>> So cannot provide detailed instructions. Just my point of view.
>>>>>>>>
>>>>>>>> You can look
>>>>>>>> https://kubernetes.io/docs/concepts/extend-kubernetes/operator/
>>>>>>>> https://www.magalix.com/blog/creating-custom-kubernetes-operators
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> On Tue, Aug 25, 2020 at 7:41 PM Pavithra Mohanraja <
>>>>>>>> pavimohan3004 at gmail.com> wrote:
>>>>>>>>
>>>>>>>>> Hi,
>>>>>>>>>
>>>>>>>>> It would be helpful if you could elaborate what has to be done for
>>>>>>>>> kubernetes pods when you mention sip ingress
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Thanks,
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Pavithra
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> On Tue, Aug 25, 2020, 9:32 PM Sergey Safarov <s.safarov at gmail.com>
>>>>>>>>> wrote:
>>>>>>>>>
>>>>>>>>>> Lot of issues with static IP in Kubernetes.
>>>>>>>>>>
>>>>>>>>>> Looks as need deploy "sip ingress" like "HTTP/HTTPS ingress" and
>>>>>>>>>> then route calls to pods.
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> On Tue, Aug 25, 2020 at 4:40 PM Pavithra Mohanraja <
>>>>>>>>>> pavimohan3004 at gmail.com> wrote:
>>>>>>>>>>
>>>>>>>>>>> Hi,
>>>>>>>>>>>
>>>>>>>>>>> I am configuring kamailio IMS as kubernetes pods .
>>>>>>>>>>> so each component will be configured as separate pod .
>>>>>>>>>>> In order to establish a connection between pods , I am
>>>>>>>>>>> configuring bind9 dns server in pcscf pod itself. Communication is
>>>>>>>>>>> happening via Pod IP address.
>>>>>>>>>>>
>>>>>>>>>>> Is there any possibility to have the communication using cluster
>>>>>>>>>>> IP . If anybody is aware of kubernetes, Please help me in this regard.
>>>>>>>>>>>
>>>>>>>>>>> I have my /etc/resolv.conf file in pods with
>>>>>>>>>>> nameserver <clusterIP>
>>>>>>>>>>> search <cluster-dns-domain-name>
>>>>>>>>>>>
>>>>>>>>>>> Please help.
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> Thanks,
>>>>>>>>>>> Pavithra
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> _______________________________________________
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> Kamailio (SER) - Users Mailing List
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> sr-users at lists.kamailio.org
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> _______________________________________________
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> Kamailio (SER) - Users Mailing List
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> sr-users at lists.kamailio.org
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> _______________________________________________
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Kamailio (SER) - Users Mailing List
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> sr-users at lists.kamailio.org
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>
>>>>>>>> _______________________________________________
>>>>>>>>
>>>>>>>>
>>>>>>>> Kamailio (SER) - Users Mailing List
>>>>>>>>
>>>>>>>>
>>>>>>>> sr-users at lists.kamailio.org
>>>>>>>>
>>>>>>>>
>>>>>>>> https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>>
>>>>>>> Kamailio (SER) - Users Mailing List
>>>>>>>
>>>>>>> sr-users at lists.kamailio.org
>>>>>>>
>>>>>>> https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
>>>>>>>
>>>>>>> --
>>>>>> Regards,
>>>>>>
>>>>>> David Villasmil
>>>>>> email: david.villasmil.work at gmail.com
>>>>>> phone: +34669448337
>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>>
>>>>>>
>>>>>> Kamailio (SER) - Users Mailing List
>>>>>>
>>>>>>
>>>>>> sr-users at lists.kamailio.org
>>>>>>
>>>>>>
>>>>>> https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>
>>>
>>
>> --
> Regards,
>
> David Villasmil
> email: david.villasmil.work at gmail.com
> phone: +34669448337
>
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