Kubernetes Cluster 에서 사용할 스토리지로 외부의 Glusterfs 를 Dynamic Provisioning 스토리지로 사용할 경우에 대한 구축 방법에 대한 앞선 포스팅(http://bryan.wiki/283)에 더하여, 또 다른 Dynamic Provisioning 솔루션이 대해 정리해 보겠다. 즉, 본 시리즈(1~3)의 현재까지의 구축 환경을 그대로 활용하여, 추가로 Glusterfs를 컨테이너 방식으로 각 Minion 의 Pod(DaemonSet)에 위치 시켜 각 Minion 에 추가장착된 HDD(그림에서는 /dev/sdx 로 표시)를 glusterfs의 분산 디스크로 사용, Heketi API 를 통한 kubernetes 와의 통합된 환경을 구축하고 실제로 PV를 만들고 테스트해 보기로 한다.


이러한 Hyper-Converged 방식을 쓰게 되면 외부의 Glusterfs 클러스터 등의 별도 스토리지 솔루션이 불필요하게 되며, 필요한 만큼 스토리지를 갖춘 Minion 노드를 추가하게 되면 Kubernetes 를 위함 컴퓨팅 자원과 스토리지 공간이 함께 늘어나는, 진정한 Scalable Comupting Cluster를 갖출 수 있게 된다.


Static Provisioning 에 대해서는 이전 포스팅에서 이미 간략히 설명했으므로, 별도 언급은 하지 않겠으며, 이러한 Dynamic Provisioning 이 가능한 스토리지 방식으로는 GlusterFS  외에도 OpenStack Cinder, AWS EBS, GCE Persistent Disk, Ceph RBD, NetApp Trident 등이 있다.





* 기존 1~3 편에서 작업했던 설정 환경을 그대로 사용하여, kubenode1/2/3 을 각각 GlusterFs pod를 통해 Gluster 스토리지 노드로 사용하는 구성이다.

* 참고 자료: gluster_kubernetes.pdf



사전 준비(Prerequisites)


* 모든 k8s 노드에서 GlusterFS Client, SELinux 설정(setsebool)

[root@kubenode01 ~]# yum install -y centos-release-gluster310.noarch

[root@kubenode01 ~]# yum install -y glusterfs-client

[root@kubenode01 ~]# setsebool -P virt_sandbox_use_fusefs on



github gluster-kubernetes repo 다운로드


[root@kubemaster ~]# git clone https://github.com/gluster/gluster-kubernetes.git

Cloning into 'gluster-kubernetes'...

remote: Counting objects: 2024, done.

remote: Compressing objects: 100% (14/14), done.

remote: Total 2024 (delta 5), reused 9 (delta 2), pack-reused 2008

Receiving objects: 100% (2024/2024), 987.73 KiB | 456.00 KiB/s, done.

Resolving deltas: 100% (1041/1041), done.


[root@kubemaster ~]# cd gluster-kubernetes/deploy

[root@kubemaster deploy]# cp topology.json.sample topology.json

[root@kubemaster deploy]# vi topology.json


{
    "clusters": [
        {
            "nodes": [
                {
                    "node": {
                        "hostnames": {
                            "manage": [
                                "kubenode1"
                            ],
                            "storage": [
                                "10.255.10.171"
                            ]
                        },
                        "zone": 1
                    },
                    "devices": [
                        "/dev/sdb"
                    ]
                },
                {
                    "node": {
                        "hostnames": {
                            "manage": [
                                "kubenode2"
                            ],
                            "storage": [
                                "10.255.20.170"
                            ]
                        },
                        "zone": 1
                    },
                    "devices": [
                        "/dev/sdb"
                    ]
                },
                {
                    "node": {
                        "hostnames": {
                            "manage": [
                                "kubenode3"
                            ],
                            "storage": [
                                "10.255.20.171"
                            ]
                        },
                        "zone": 1
                    },
                    "devices": [
                        "/dev/sdb"
                    ]
                }
            ]
        }
    ]
}


Glusterfs, Heketi Pod와 Svc 설치 - gk-deploy 실행


[root@kubemaster deploy]# ./gk-deploy -g

Welcome to the deployment tool for GlusterFS on Kubernetes and OpenShift.


Before getting started, this script has some requirements of the execution

environment and of the container platform that you should verify.


The client machine that will run this script must have:

 * Administrative access to an existing Kubernetes or OpenShift cluster

 * Access to a python interpreter 'python'


Each of the nodes that will host GlusterFS must also have appropriate firewall

rules for the required GlusterFS ports:

 * 2222  - sshd (if running GlusterFS in a pod)

 * 24007 - GlusterFS Management

 * 24008 - GlusterFS RDMA

 * 49152 to 49251 - Each brick for every volume on the host requires its own

   port. For every new brick, one new port will be used starting at 49152. We

   recommend a default range of 49152-49251 on each host, though you can adjust

   this to fit your needs.


The following kernel modules must be loaded:

 * dm_snapshot

 * dm_mirror

 * dm_thin_pool


For systems with SELinux, the following settings need to be considered:

 * virt_sandbox_use_fusefs should be enabled on each node to allow writing to

   remote GlusterFS volumes


In addition, for an OpenShift deployment you must:

 * Have 'cluster_admin' role on the administrative account doing the deployment

 * Add the 'default' and 'router' Service Accounts to the 'privileged' SCC

 * Have a router deployed that is configured to allow apps to access services

   running in the cluster


Do you wish to proceed with deployment?


[Y]es, [N]o? [Default: Y]: 

Using Kubernetes CLI.

Using namespace "default".

Checking for pre-existing resources...

  GlusterFS pods ... not found.

  deploy-heketi pod ... not found.

  heketi pod ... not found.

Creating initial resources ... serviceaccount "heketi-service-account" created

clusterrolebinding "heketi-sa-view" created

clusterrolebinding "heketi-sa-view" labeled

OK

node "kubenode1" labeled

node "kubenode2" labeled

node "kubenode3" labeled

daemonset "glusterfs" created

Waiting for GlusterFS pods to start ... OK

secret "heketi-config-secret" created

secret "heketi-config-secret" labeled

service "deploy-heketi" created

deployment "deploy-heketi" created

Waiting for deploy-heketi pod to start ... OK

Creating cluster ... ID: d9b90e275621648ad6aacb67759662c9

Creating node kubenode1 ... ID: 858e047eb0cb8943be7b1cd947a26e3c

Adding device /dev/sdb ... OK

Creating node kubenode2 ... ID: 6e9368eea425afb561846576c7b7df70

Adding device /dev/sdb ... OK

Creating node kubenode3 ... ID: 0c3da29a5fa92681a5bc64cf32e9e7e5

Adding device /dev/sdb ... OK

heketi topology loaded.

Saving /tmp/heketi-storage.json

secret "heketi-storage-secret" created

endpoints "heketi-storage-endpoints" created

service "heketi-storage-endpoints" created

job "heketi-storage-copy-job" created

service "heketi-storage-endpoints" labeled

pod "deploy-heketi-2199298601-mrh2p" deleted

service "deploy-heketi" deleted

job "heketi-storage-copy-job" deleted

deployment "deploy-heketi" deleted

secret "heketi-storage-secret" deleted

service "heketi" created

deployment "heketi" created

Waiting for heketi pod to start ... OK


heketi is now running and accessible via http://172.31.45.204:8080 . To run

administrative commands you can install 'heketi-cli' and use it as follows:


  # heketi-cli -s http://172.31.45.204:8080 --user admin --secret '<ADMIN_KEY>' cluster list


You can find it at https://github.com/heketi/heketi/releases . Alternatively,

use it from within the heketi pod:


  # /usr/bin/kubectl -n default exec -it <HEKETI_POD> -- heketi-cli -s http://localhost:8080 --user admin --secret '<ADMIN_KEY>' cluster list


For dynamic provisioning, create a StorageClass similar to this:


---

apiVersion: storage.k8s.io/v1beta1

kind: StorageClass

metadata:

  name: glusterfs-storage

provisioner: kubernetes.io/glusterfs

parameters:

  resturl: "http://172.31.45.204:8080"



Deployment complete!

* DaemonSet 의 모든 pod들(gusterfs-xxxxx)의 기동에 시간이 많이 걸릴 경우, Waiting for ... pods not found. 메시지를 남기고 종료되는 경우가 있을 수 있다. 이 때는 daemonset 의 pod가 모두 Ready 상태로 기동되기를 기다렸다가 위의 gkdeploy 과정을 다시 수행하면 된다.


Heketi CLI 를 통한 Gluster Cluster 정상 동작 확인


[root@kubemaster deploy]# echo "export HEKETI_CLI_SERVER=$(kubectl get svc/heketi --template 'http://{{.spec.clusterIP}}:{{(index .spec.ports 0).port}}')" | tee -a ~/.bashrc

export HEKETI_CLI_SERVER=http://10.128.23.39:8080


[root@kubemaster deploy]# yum install -y heketi-client

[root@kubemaster deploy]# source ~/.bashrc

[root@kubemaster deploy]# heketi-cli cluster list

Clusters:

d9b90e275621648ad6aacb67759662c9


[root@kubemaster deploy]# heketi-cli cluster info d9b90e275621648ad6aacb67759662c9

Cluster id: d9b90e275621648ad6aacb67759662c9

Nodes:

0c3da29a5fa92681a5bc64cf32e9e7e5

6e9368eea425afb561846576c7b7df70

858e047eb0cb8943be7b1cd947a26e3c

Volumes:

254add2981864590710f85567895758a


[root@kubemaster ~]# heketi-cli volume info 254add2981864590710f85567895758a

Name: heketidbstorage

Size: 2

Volume Id: 254add2981864590710f85567895758a

Cluster Id: d9b90e275621648ad6aacb67759662c9

Mount: 10.255.10.171:heketidbstorage

Mount Options: backup-volfile-servers=10.255.20.170,10.255.20.171

Durability Type: replicate

Distributed+Replica: 3



* Gluster Volume 생성 테스트

[root@kubemaster ~]# heketi-cli volume create --size=1

Name: vol_5a876cb91239b4de80c3a00797888254

Size: 1

Volume Id: 5a876cb91239b4de80c3a00797888254

Cluster Id: d9b90e275621648ad6aacb67759662c9

Mount: 10.255.10.171:vol_5a876cb91239b4de80c3a00797888254

Mount Options: backup-volfile-servers=10.255.20.170,10.255.20.171

Durability Type: replicate

Distributed+Replica: 3


[root@kubemaster ~]# heketi-cli volume delete 5a876cb91239b4de80c3a00797888254

Volume 5a876cb91239b4de80c3a00797888254 deleted



Kubernetes 에서 Gluster PV 사용을 위한 준비와 PV 생성 테스트

  • StorageClass 를 생성한다
  • metadata의 name 에서 지정하는 값이, 실제로 사용시 요청되는 persistent volume claim(pvc) 에서 annotation 의 값으로 사용된다
  • resturl 에는 위에서 생성한 환경 변수 HEKETI_CLI_SERVER 의 값과 동일한 URL을 등록한다

[root@kubemaster ~]# mkdir gluster-storage-setup-test

[root@kubemaster ~]# cd gluster-storage-setup-test/

[root@kubemaster gluster-storage-setup-test]# vi 00-gluster-storageclass.yaml

apiVersion: storage.k8s.io/v1beta1
kind: StorageClass
metadata:
  name: glusterfs-storage
provisioner: kubernetes.io/glusterfs
parameters:
  resturl: "http://10.128.23.39:8080"


[root@kubemaster gluster-storage-setup-test]# kubectl create -f 00-gluster-storageclass.yaml 

storageclass "glusterfs-storage" created


* 1 GB 용량의 pvc(스토리지 할당 요청)을 만들어서 테스트해 본다

[root@kubemaster gluster-storage-setup-test]# vi test-pvc-1gi.yaml

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
 name: test-dyn-pvc
 annotations:
   volume.beta.kubernetes.io/storage-class: glusterfs-storage
spec:
 accessModes:
  - ReadWriteOnce
 resources:
   requests:
     storage: 1Gi

* accessModes는 RWO(ReadWriteOnce), ROX(ReadOnlyMany), RWX(ReadWriteMany) 의 3 종류가 있다


[root@kubemaster gluster-storage-setup-test]# kubectl create -f test-pvc-1gi.yaml 

persistentvolumeclaim "test-dyn-pvc" created


[root@kubemaster gluster-storage-setup-test]# kubectl get pvc,pv

NAME               STATUS    VOLUME                                     CAPACITY   ACCESSMODES   STORAGECLASS        AGE

pvc/test-dyn-pvc   Bound     pvc-1f3065fe-8900-11e7-827f-08002729d0c4   1Gi        RWO           glusterfs-storage   11s


NAME                                          CAPACITY   ACCESSMODES   RECLAIMPOLICY   STATUS    CLAIM                  STORAGECLASS        REASON    AGE

pv/pvc-1f3065fe-8900-11e7-827f-08002729d0c4   1Gi        RWO           Delete          Bound     default/test-dyn-pvc   glusterfs-storage             6s

* test-dyn-pvc 에 대응하는 pv가 만들어져 있음을 볼 수 있다



생성된 PV를 사용하는 Pod 를 생성하고 마운트된 볼륨 내용을 다뤄 보자


[root@kubemaster gluster-storage-setup-test]# vi test-nginx-pvc.yaml 

apiVersion: v1
kind: Pod
metadata:
  name: nginx-pod-pv
  labels:
    name: nginx-pod-pv
spec:
  containers:
  - name: nginx-pod-pv
    image: gcr.io/google_containers/nginx-slim:0.8
    ports:
    - name: web
      containerPort: 80
    volumeMounts:
    - name: gluster-vol1
      mountPath: /usr/share/nginx/html
  volumes:
  - name: gluster-vol1
    persistentVolumeClaim:
      claimName: test-dyn-pvc

[root@kubemaster gluster-storage-setup-test]# kubectl create -f test-nginx-pvc.yaml 

pod "nginx-pod-pv" created

* Pod 내의 마운트포인트는 nginx 기본 html 저장위치인 /usr/share/nginx/html

* PV 이름을 직접 사용하는 것이 아니라 pvc 명인 test-dyn-pvc을 사용한다



[root@kubemaster gluster-storage-setup-test]# kubectl get pods -o wide

NAME                         READY     STATUS    RESTARTS   AGE       IP               NODE

busybox-for-dnstest          1/1       Running   29         1d        172.31.35.72     kubenode2

glusterfs-22v6s              1/1       Running   0          9h        10.255.20.171    kubenode3

glusterfs-pjsvb              1/1       Running   0          9h        10.255.10.171    kubenode1

glusterfs-tpd0h              1/1       Running   0          9h        10.255.20.170    kubenode2

heketi-2660258935-spb5g      1/1       Running   0          9h        172.31.45.204    kubenode3

hostnames-2923313648-3104j   1/1       Running   0          1d        172.31.35.73     kubenode2

hostnames-2923313648-h4n8j   1/1       Running   0          1d        172.31.45.199    kubenode3

hostnames-2923313648-r89h4   1/1       Running   0          1d        172.31.205.197   kubenode1

nginx-pod-pv                 1/1       Running   0          3m        172.31.35.77     kubenode2


[root@kubemaster gluster-storage-setup-test]# kubectl exec -it nginx-pod-pv -- /bin/sh

# df -h

Filesystem                                                                                      Size  Used Avail Use% Mounted on

...

10.255.10.171:vol_989e89f4758c8749c00ed6fd2fc1db92                                             1016M   33M  983M   4% /usr/share/nginx/html

...

# echo 'Hello World from GlusterFS!!!' > /usr/share/nginx/html/index.html

# exit


[root@kubemaster gluster-storage-setup-test]# curl http://172.31.35.77

Hello World from GlusterFS!!!

* Web 서버의 source, index.html 을 작성(변경)

* nginx Pod 의 IP를 이용해서 URL에 대한 Web 접속 테스트



GlusterFS Pod(Gluster 노드 역할) 내부에서 스토리지 내부 데이터 직접 확인


[root@kubemaster ~]# kubectl exec -it glusterfs-22v6s -- /bin/sh

sh-4.2# mount | grep heketi

/dev/mapper/cl-root on /var/lib/heketi type xfs (rw,relatime,seclabel,attr2,inode64,noquota)

/dev/mapper/vg_be4e161a83f2835fb8e9c61ee2513a69-brick_8ff06f0a54b9155179dd70a5fa02784b on /var/lib/heketi/mounts/vg_be4e161a83f2835fb8e9c61ee2513a69/brick_8ff06f0a54b9155179dd70a5fa02784b type xfs (rw,noatime,seclabel,nouuid,attr2,inode64,logbsize=256k,sunit=512,swidth=512,noquota)

/dev/mapper/vg_be4e161a83f2835fb8e9c61ee2513a69-brick_7cebe446228298f5b11b171567edf30f on /var/lib/heketi/mounts/vg_be4e161a83f2835fb8e9c61ee2513a69/brick_7cebe446228298f5b11b171567edf30f type xfs (rw,noatime,seclabel,nouuid,attr2,inode64,logbsize=256k,sunit=512,swidth=512,noquota)

sh-4.2# mount | grep heketi

sh-4.2# cd /var/lib/heketi/mounts/vg_be4e161a83f2835fb8e9c61ee2513a69/brick_7cebe446228298f5b11b171567edf30f/brick

sh-4.2# cat index.html

Hello World from GlusterFS!!!



불필요한 테스트용 볼륨, Pod 삭제


[root@kubemaster gluster-storage-setup-test]# kubectl delete -f test-nginx-pvc.yaml 

pod "nginx-pod-pv" deleted


[root@kubemaster gluster-storage-setup-test]# kubectl delete -f test-pvc-1gi.yaml 

persistentvolumeclaim "test-dyn-pvc" deleted


[root@kubemaster gluster-storage-setup-test]# kubectl get pv

No resources found.


[root@kubemaster gluster-storage-setup-test]# heketi-cli volume list

Id:254add2981864590710f85567895758a    Cluster:d9b90e275621648ad6aacb67759662c9    Name:heketidbstorage

* kubectl 로 pvc 삭제를 수행하면 pv가 삭제되고, Heketi CLI 에서 해당 Gluster Volume 이 삭제되어 있음을 확인할 수 있다

  (heketidbstorage 볼륨은 Heketi 의 메타데이터를 저장하는 기본 볼륨으로, 삭제하지 말 것)




- Barracuda -


[관련 글 목록]

[Technical/Cloud, 가상화, PaaS] - [Kubernetes] CentOS 7.3 으로 Kubernetes Cluster 구성(with Flannel)-1/4

[Technical/Cloud, 가상화, PaaS] - [Kubernetes] CentOS 7.3 으로 Kubernetes Cluster 구성(노드 추가하기)-2/4

[Technical/Cloud, 가상화, PaaS] - [Kubernetes] 1.7.3/1.7.4, kubeadm 으로 L3 네트워크 기반 Cluster 구성(with Calico CNI)-3/4

[Technical/Cloud, 가상화, PaaS] - [Kubernetes] Hyper-converged GlusterFs integration with Heketi -4/4

[Technical/Cloud, 가상화, PaaS] - [GlusterFS & Kubernetes] External Gluster PV with Heketi CLI/Rest API



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Barracuda

Bryan의 MemoLog. 쉽게 익혀 보는 IT 실습과 개념원리, 코딩 세계의 얕은 맛보기들, 평범한 삶 주변의 현상 그리고 進上, 眞想, 진상들