[SR-Users] Kamailio IMS as kubernetes pods

Wed Aug 26 19:01:48 CEST 2020

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
>>>>
>>>
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