[SR-Users] Kamailio IMS as kubernetes pods

David Villasmil david.villasmil.work at gmail.com
Fri Aug 28 21:02:26 CEST 2020 

Abdirahman,

Thanks for the pointer, that worked like a charm!

David

On Thu, 27 Aug 2020 at 20:11, Pavithra Mohanraja <pavimohan3004 at gmail.com>
wrote:

> Hi Abdirahman,
>
> One small doubt . In kamailio IMS server, we have dns configurations using
> bind9 with SRV records pointing a port for every ip address .
>
> My domain name is sip.example.com
>
> Pcscf.sip.example.com:4060
> Icscf.sip.example.com:4070
> scscf.sip.example.com:4080
> hss.sip.example.com
>
>
> So this is how the dns server will be in my case.
>
> The same domain names are configured as alias in my respective  cscf
> config files.
>
> When you talk about nameserver . How this has to be configured using
> coredns/kubedns setting clusterIP : None
>
> How this can be done from your point of view using coredns.
>
> Kindly help me with this
>
> Thanks,
> Pavithra
>
> On Thu, Aug 27, 2020, 11:55 PM David Villasmil <
> david.villasmil.work at gmail.com> wrote:
>
>> Interesting! I’ll be testing that very soon! Many thanks!!
>>
>> On Thu, 27 Aug 2020 at 14:53, Abdirahman A. Osman <
>> abdirahman.osm at gmail.com> wrote:
>>
>>> 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
>>>>
>>>>
>>>>
>>>
>>> --
>> Regards,
>>
>> David Villasmil
>> email: david.villasmil.work at gmail.com
>> phone: +34669448337
>>
>>
>>
>
> --
Regards,

David Villasmil
email: david.villasmil.work at gmail.com
phone: +34669448337
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