K8S - Volume - NFS 卷的简介和使用
在之前的文章里已经介绍了 K8S 中两个简单卷类型 hostpath 和 emptydir
k8s - Volume 简介和HostPath的使用
K8S - Emptydir - 取代ELK 使用fluentd 构建logging saidcar
但是这两种卷都有同1个限制， 就是依赖于 k8s nodes的空间
如果某个service pod中需要的volumn 空间很大， 这时我们就需要考虑网络磁盘方案， 其中NAS 类型的Volume 是常用且简单的选择之一
找1个VM安装NFS服务
先找个vm
首先我们需要1个NAS 服务 provider
gateman@MoreFine-S500:~$ gcloud compute ssh tf-vpc0-subnet0-main-server
WARNING: This command is using service account impersonation. All API calls will be executed as [terraform@jason-hsbc.iam.gserviceaccount.com].
WARNING: This command is using service account impersonation. All API calls will be executed as [terraform@jason-hsbc.iam.gserviceaccount.com].
No zone specified. Using zone [europe-west2-c] for instance: [tf-vpc0-subnet0-main-server].
Linux tf-vpc0-subnet0-main-server 5.10.0-32-cloud-amd64 #1 SMP Debian 5.10.223-1 (2024-08-10) x86_64
The programs included with the Debian GNU/Linux system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.
Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
permitted by applicable law.
Last login: Sat Sep 7 15:27:35 2024 from 112.94.250.239
gateman@tf-vpc0-subnet0-main-server:~$ df -h
Filesystem Size Used Avail Use% Mounted on
udev 7.9G 0 7.9G 0% /dev
tmpfs 1.6G 1.2M 1.6G 1% /run
/dev/sda1 59G 23G 34G 41% /
tmpfs 7.9G 0 7.9G 0% /dev/shm
tmpfs 5.0M 0 5.0M 0% /run/lock
/dev/sda15 124M 11M 114M 9% /boot/efi
tmpfs 1.6G 0 1.6G 0% /run/user/1000
gateman@tf-vpc0-subnet0-main-server:~$
还有30GB 空间， 应该还行
创建 共享文件夹
gateman@tf-vpc0-subnet0-main-server:~$ sudo su -
root@tf-vpc0-subnet0-main-server:~# mkdir -p /nfs/k8s-share
root@tf-vpc0-subnet0-main-server:~#
安装nfs
root@tf-vpc0-subnet0-main-server:~# apt-get install nfs-kernel-server
修改配置
root@tf-vpc0-subnet0-main-server:~# cat /etc/exports
# /etc/exports: the access control list for filesystems which may be exported
# to NFS clients. See exports(5).
#
# Example for NFSv2 and NFSv3:
# /srv/homes hostname1(rw,sync,no_subtree_check) hostname2(ro,sync,no_subtree_check)
#
# Example for NFSv4:
# /srv/nfs4 gss/krb5i(rw,sync,fsid=0,crossmnt,no_subtree_check)
# /srv/nfs4/homes gss/krb5i(rw,sync,no_subtree_check)
#
/nfs/k8s-share 192.168.0.0/16(rw,sync,no_subtree_check,no_root_squash)
只允许同1个局域网的vm访问
注意rw,sync,no_subtree_check,no_root_squash 这里之间不能有空格， 否则会有bad option list error.
重启nfs 服务
root@tf-vpc0-subnet0-main-server:~# vi /etc/exports
root@tf-vpc0-subnet0-main-server:~# systemctl restart nfs-server
root@tf-vpc0-subnet0-main-server:~# systemctl status nfs-server
● nfs-server.service - NFS server and services
Loaded: loaded (/lib/systemd/system/nfs-server.service; enabled; vendor preset: enabled)
Active: active (exited) since Fri 2024-09-13 19:29:44 UTC; 2s ago
Process: 158390 ExecStartPre=/usr/sbin/exportfs -r (code=exited, status=0/SUCCESS)
Process: 158391 ExecStart=/usr/sbin/rpc.nfsd $RPCNFSDARGS (code=exited, status=0/SUCCESS)
Main PID: 158391 (code=exited, status=0/SUCCESS)
CPU: 17ms
Sep 13 19:29:43 tf-vpc0-subnet0-main-server systemd[1]: Starting NFS server and services...
Sep 13 19:29:44 tf-vpc0-subnet0-main-server systemd[1]: Finished NFS server and services.
找另1台测试 mount 这个nfs drive
首先等录另一台， 需要先安装nfs client (nfs-common)
否则mount 不上
root@tf-vpc0-subnet0-mysql0:~# apt install nfs-common
然后 可以用showmount 看一下主机有什么shared 的drive 可以mount
root@tf-vpc0-subnet0-mysql0:~# showmount -e 192.168.0.35
创建1个mount point
root@tf-vpc0-subnet0-mysql0:~# mkdir -p /mnt/nfs-test
挂载主机NAS drive 到本机 mountpoint
root@tf-vpc0-subnet0-mysql0:~# mount -t nfs 192.168.0.35:/nfs/k8s-share /mnt/nfs-test
在K8S 测试 case 1
编写deployment yaml
apiVersion: apps/v1
kind: Deployment
metadata:
labels: # label of this deployment
app: cloud-order # custom defined
author: nvd11
name: deployment-cloud-order # name of this deployment
namespace: default
spec:
replicas: 3 # desired replica count, Please note that the replica Pods in a Deployment are typically distributed across multiple nodes.
revisionHistoryLimit: 10 # The number of old ReplicaSets to retain to allow rollback
selector: # label of the Pod that the Deployment is managing,, it's mandatory, without it , we will get this error
# error: error validating data: ValidationError(Deployment.spec.selector): missing required field "matchLabels" in io.k8s.apimachinery.pkg.apis.meta.v1.LabelSelector ..
matchLabels:
app: cloud-order
strategy: # Strategy of upodate
type: RollingUpdate # RollingUpdate or Recreate
rollingUpdate:
maxSurge: 25% # The maximum number of Pods that can be created over the desired number of Pods during the update
maxUnavailable: 25% # The maximum number of Pods that can be unavailable during the update
template: # Pod template
metadata:
labels:
app: cloud-order # label of the Pod that the Deployment is managing. must match the selector, otherwise, will get the error Invalid value: map[string]string{"app":"bq-api-xxx"}: `selector` does not match template `labels`
spec: # specification of the Pod
containers:
- image: europe-west2-docker.pkg.dev/jason-hsbc/my-docker-repo/cloud-order:1.1.0 # image of the container
imagePullPolicy: Always
name: container-cloud-order
command: ["bash"]
args:
- "-c"
- |
java -jar -Dserver.port=8080 app.jar --spring.profiles.active=$APP_ENVIRONMENT --logging.file.name=/app/logs/app.log
env: # set env varaibles
- name: APP_ENVIRONMENT # name of the environment variable
value: prod # value of the environment variable
volumeMounts: # write log here
- name: volume-nfs-log
mountPath: /app/logs/
readOnly: false # read only is set to false
ports:
- containerPort: 8080
name: cloud-order
volumes:
- name: volume-nfs-log
nfs:
server: 192.168.0.35
path: /nfs/k8s-share # nfs share path
readOnly: false
restartPolicy: Always # Restart policy for all containers within the Pod
terminationGracePeriodSeconds: 10 # The period of time in seconds given to the Pod to terminate gracefully
这里我定义了1个 nfs 的volumes
volumes:
- name: volume-nfs-log
nfs:
server: 192.168.0.35
path: /nfs/k8s-share # nfs share path
readOnly: false
并在容器里挂载在/app/logs/
启动容器
这时容器启动失败
gateman@MoreFine-S500:nfs$ kubectl apply -f deployment-cloud-order-fluentd-nfs-case1.yaml
deployment.apps/deployment-cloud-order created
gateman@MoreFine-S500:nfs$ kubectl get pods
NAME READY STATUS RESTARTS AGE
deployment-bq-api-service-6f6ffc7866-58drw 1/1 Running 5 (5d1h ago) 10d
deployment-bq-api-service-6f6ffc7866-8djx9 1/1 Running 6 (5d1h ago) 30d
deployment-bq-api-service-6f6ffc7866-mxwcq 1/1 Running 16 (5d1h ago) 74d
deployment-bq-api-service-6f6ffc7866-x8pl6 1/1 Running 3 (5d1h ago) 10d
deployment-cloud-order-5f45f44fbc-8vzx5 0/1 Terminating 0 5m19s
deployment-cloud-order-5f45f44fbc-b2p5r 0/1 Terminating 0 5m19s
deployment-cloud-order-5f45f44fbc-xnnr7 0/1 Terminating 0 5m19s
deployment-cloud-order-5f46d97659-8nsln 0/1 ContainerCreating 0 8s
deployment-cloud-order-5f46d97659-9pvsb 0/1 ContainerCreating 0 8s
deployment-cloud-order-5f46d97659-jsmsm 0/1 ContainerCreating 0 8s
deployment-fluentd-test-56bd589c6-dptxl 1/1 Running 1 (5d1h ago) 5d1h
dns-test 0/1 Completed 0 28d
gateman@MoreFine-S500:nfs$ kubectl describe po deployment-cloud-order-5f46d97659-jsmsm | tail -n 20
Path: /nfs/k8s-share
ReadOnly: false
kube-api-access-d54rh:
Type: Projected (a volume that contains injected data from multiple sources)
TokenExpirationSeconds: 3607
ConfigMapName: kube-root-ca.crt
ConfigMapOptional: <nil>
DownwardAPI: true
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 30s default-scheduler Successfully assigned default/deployment-cloud-order-5f46d97659-jsmsm to k8s-node0
Warning FailedMount 14s (x6 over 29s) kubelet MountVolume.SetUp failed for volume "volume-nfs-log" : mount failed: exit status 32
Mounting command: mount
Mounting arguments: -t nfs 192.168.0.35:/nfs/k8s-share /var/lib/kubelet/pods/00850c02-3766-4481-93bc-089f19c1547b/volumes/kubernetes.io~nfs/volume-nfs-log
Output: mount: /var/lib/kubelet/pods/00850c02-3766-4481-93bc-089f19c1547b/volumes/kubernetes.io~nfs/volume-nfs-log: bad option; for several filesystems (e.g. nfs, cifs) you might need a /sbin/mount.<type> helper program.
Output: mount: /var/lib/kubelet/pods/00850c02-3766-4481-93bc-089f19c1547b/volumes/kubernetes.io~nfs/volume-nfs-log: bad option; for several filesystems (e.g. nfs, cifs) you might need a /sbin/mount. helper program.
难道要在k8s nodes 里安装nfs-common?
在K8S 测试 case 2 - 只在k8s-node0 1个node 安装nfs-common
gateman@MoreFine-S500:nfs$ kubectl get po -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
deployment-bq-api-service-6f6ffc7866-58drw 1/1 Running 5 (5d1h ago) 10d 10.244.2.235 k8s-node0 <none> <none>
deployment-bq-api-service-6f6ffc7866-8djx9 1/1 Running 6 (5d1h ago) 30d 10.244.1.149 k8s-node1 <none> <none>
deployment-bq-api-service-6f6ffc7866-mxwcq 1/1 Running 16 (5d1h ago) 74d 10.244.2.234 k8s-node0 <none> <none>
deployment-bq-api-service-6f6ffc7866-x8pl6 1/1 Running 3 (5d1h ago) 10d 10.244.1.150 k8s-node1 <none> <none>
deployment-cloud-order-5f46d97659-drpqk 0/1 ContainerCreating 0 43s <none> k8s-node3 <none> <none>
deployment-cloud-order-5f46d97659-g65zz 0/1 ContainerCreating 0 43s <none> k8s-node1 <none> <none>
deployment-cloud-order-5f46d97659-jmld7 1/1 Running 0 43s 10.244.2.237 k8s-node0 <none> <none>
deployment-fluentd-test-56bd589c6-dptxl 1/1 Running 1 (5d1h ago) 5d2h 10.244.3.169 k8s-node3 <none> <none>
dns-test 0/1 Completed 0 28d 10.244.1.92 k8s-node1 <none> <none>
gateman@MoreFine-S500:nfs$ kubectl describe po deployment-cloud-order-5f46d97659-g65zz | tail -n 20
ReadOnly: false
kube-api-access-nq7d9:
Type: Projected (a volume that contains injected data from multiple sources)
TokenExpirationSeconds: 3607
ConfigMapName: kube-root-ca.crt
ConfigMapOptional: <nil>
DownwardAPI: true
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 2m12s default-scheduler Successfully assigned default/deployment-cloud-order-5f46d97659-g65zz to k8s-node1
Warning FailedMount 9s kubelet Unable to attach or mount volumes: unmounted volumes=[volume-nfs-log], unattached volumes=[volume-nfs-log kube-api-access-nq7d9]: timed out waiting for the condition
Warning FailedMount 4s (x9 over 2m11s) kubelet MountVolume.SetUp failed for volume "volume-nfs-log" : mount failed: exit status 32
Mounting command: mount
Mounting arguments: -t nfs 192.168.0.35:/nfs/k8s-share /var/lib/kubelet/pods/020d15ee-8ee5-4846-9d66-afd658a9073b/volumes/kubernetes.io~nfs/volume-nfs-log
Output: mount: /var/lib/kubelet/pods/020d15ee-8ee5-4846-9d66-afd658a9073b/volumes/kubernetes.io~nfs/volume-nfs-log: bad option; for several filesystems (e.g. nfs, cifs) you might need a /sbin/mount.<type> helper program.
果然只有k8s-node0 里的pod 启动成功
在K8S 测试 case 3 - 在其他nodes 里也安装nfs-common
gateman@MoreFine-S500:nfs$ kubectl get po -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
deployment-bq-api-service-6f6ffc7866-58drw 1/1 Running 5 (5d1h ago) 10d 10.244.2.235 k8s-node0 <none> <none>
deployment-bq-api-service-6f6ffc7866-8djx9 1/1 Running 6 (5d1h ago) 30d 10.244.1.149 k8s-node1 <none> <none>
deployment-bq-api-service-6f6ffc7866-mxwcq 1/1 Running 16 (5d1h ago) 74d 10.244.2.234 k8s-node0 <none> <none>
deployment-bq-api-service-6f6ffc7866-x8pl6 1/1 Running 3 (5d1h ago) 10d 10.244.1.150 k8s-node1 <none> <none>
deployment-cloud-order-5f46d97659-2d7nk 1/1 Running 0 8s 10.244.3.170 k8s-node3 <none> <none>
deployment-cloud-order-5f46d97659-j7dj8 1/1 Running 0 8s 10.244.1.154 k8s-node1 <none> <none>
deployment-cloud-order-5f46d97659-w7xlf 1/1 Running 0 8s 10.244.2.238 k8s-node0 <none> <none>
这次所有的pod 都是running了
检查日志文件
root@tf-vpc0-subnet0-main-server:/nfs/k8s-share# pwd
/nfs/k8s-share
root@tf-vpc0-subnet0-main-server:/nfs/k8s-share# ls -l
total 52
-rw-r--r-- 1 root root 49107 Sep 13 20:56 app.log
-rw-r--r-- 1 root root 5 Sep 13 20:01 test1.txt
app.log 生成，而且相信3个pod 都会往同1个文件写日志
检查node 的mount point
gateman@k8s-node3:~$ ls /app
ls: cannot access '/app': No such file or directory
gateman@k8s-node3:~$
可以见node server里并没有mountpoint 生成
nfs drive 被直接挂载到容器内
这也是我们expected的！