如何在Kubernetes上部署图形数据库Nebula Graph
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目录
什么是Kubernetes
Kubernetes和数据库
Kubernetes上的Nebula Graph
部署
要部署的组件
准备本地磁盘
部署本地存储卷插件
部署Nebula Graph集群
部署入口控制器(ingress-controller)
选择要部署Ingress控制器的节点
在Kubernetes中访问Nebula Graph集群
常问问题
什么是Kubernetes
Kubernetes（通常称为k8s）是一个开源的容器编排系统，旨在提供一个简单而有效的平台，用于跨主机集群自动部署，扩展和操作应用程序容器。
Kubernetes在架构上拥有一系列组件，从而实现了一种应用程序部署，维护和扩展的机制。
这些组件被设计为松散耦合和可伸缩的，以便它们可以满足各种工作负载。
Kubernetes系统的可扩展性很大程度上由Kubernetes API提供，该API可以用作可扩展的内部组件。
Kubernetes主要包含以下核心组件：
-
etcd用作所有集群数据的存储 -
apiserver提供资源操作的入口，并提供身份验证，授权，访问控制，API注册和发现的机制 -
controller manager负责维护集群的状态，例如故障检测，自动扩展，滚动更新等。 -
scheduler负责调度资源，并根据预定的调度策略将Pod调度到相应的节点。 -
kubelet负责维护容器的生命周期，还负责管理存储卷和网络 -
Container runtime负责镜像管理以及Pod和容器（CRI）的运行时 -
kube-proxy负责为kubernetes-service提供集群中的服务发现和负载均衡
除了核心组件之外，还有一些不错的组件：
-
kube-dns负责为整个集群提供DNS服务 -
Ingress Controller提供服务的外部网络访问 -
Heapster提供资源监控 -
Dashboard提供GUI图形化界面 -
Federation提供跨可用区的集群管理 -
Fluentd-elasticsearch提供集群日志收集，存储和查询
Kubernetes和数据库
数据库容器化是最近的热门话题，Kubernetes可以为数据库带来什么好处？
-
故障恢复：Kubernetes失败时将重新启动数据库应用程序，或将数据库迁移到集群中的其他运行状况正常的节点
-
存储管理：Kubernetes提供了各种存储管理解决方案，以便数据库可以采用不同的存储系统
-
负载均衡：Kubernetes Service通过将外部网络流量分配给不同的数据库副本，来提供负载均衡
-
横向可扩展性：Kubernetes可以根据当前集群的资源利用率来扩缩容，从而提高资源利用率
当前，许多数据库（例如MySQL，MongoDB和TiDB）都可以在Kubernetes上正常工作。
Kubernetes上的Nebula Graph
Nebula Graph是一个分布式的开源图形数据库，由图形化（查询引擎），存储（数据存储）和metad（元数据）组成。Kubernetes为Nebula Graph带来以下好处：
-
Kubernetes调整了graphd，metad和storaged 的不同副本之间的工作量。他们三个可以通过Kubernetes提供的dns来发现服务。
-
无论使用哪种存储系统（例如云磁盘或本地磁盘），Kubernetes都按storageclass，pvc和pv封装基础存储的详细信息。
-
Kubernetes可以在几秒钟内部署Nebula Graph集群并自动升级集群，实现用户无感知。
-
Kubernetes支持自我修复。
-
Kubernetes可以水平扩展集群，来提高Nebula性能。
在下文中，我们将向你展示使用Kubernetes部署Nebula Graph的详细信息。
部署
软件和硬件要求
以下列表是本文中部署所涉及的软件和硬件要求：
-
操作系统是CentOS-7.6.1810 x86_64
-
虚拟机配置：
-
4个CPU
-
8G内存
-
50G系统盘
-
50G数据盘A
-
50G数据盘B
-
-
Kubernetes集群是v1.16版本。
-
使用本地PV作为数据存储。
集群拓扑
以下是群集拓扑：
| 服务器IP | Nebula服务 | 角色 |
|---|---|---|
| 192.168.0.1 | k8s-master | |
| 192.168.0.2 | graphd, metad-0, storaged-0 | k8s-slave |
| 192.168.0.3 | graphd, metad-1, storaged-1 | k8s-slave |
| 192.168.0.4 | graphd, metad-2, storaged-2 | k8s-slave |
要部署的组件
-
安装Helm
-
准备本地磁盘，并安装本地存储卷插件
-
安装 Nebula Graph集群
-
安装入口控制器(ingress-controller)
安装Helm
Helm是Kubernetes软件包管理器，类似于CentOS上的yum或Ubuntu上的apt-get。Helm使得Kubernetes集群部署更加容易。由于本文没有对Helm进行详细介绍，因此请阅读Helm入门指南以了解有关Helm的更多信息。
下载并安装Helm
在终端中使用以下命令安装Helm：
[root@nebula ~]# wget https://get.helm.sh/helm-v3.0.1-linux-amd64.tar.gz
[root@nebula ~]# tar -zxvf helm/helm-v3.0.1-linux-amd64.tgz
[root@nebula ~]# mv linux-amd64/helm /usr/bin/helm
[root@nebula ~]# chmod +x /usr/bin/helm查看Helm版本
你可以使用命令查看Helm版本，helm version输出如下所示：
version.BuildInfo{
Version:"v3.0.1",
GitCommit:"7c22ef9ce89e0ebeb7125ba2ebf7d421f3e82ffa",
GitTreeState:"clean",
GoVersion:"go1.13.4"
}准备本地磁盘
下面的操作，请在每个节点配置：
创建挂载目录
[root@nebula ~]# sudo mkdir -p /mnt/disks格式化数据磁盘
[root@nebula ~]# sudo mkfs.ext4 /dev/diskA
[root@nebula ~]# sudo mkfs.ext4 /dev/diskB挂载数据磁盘
[root@nebula ~]# DISKA_UUID=$(blkid -s UUID -o value /dev/diskA)
[root@nebula ~]# DISKB_UUID=$(blkid -s UUID -o value /dev/diskB)
[root@nebula ~]# sudo mkdir /mnt/disks/$DISKA_UUID
[root@nebula ~]# sudo mkdir /mnt/disks/$DISKB_UUID
[root@nebula ~]# sudo mount -t ext4 /dev/diskA /mnt/disks/$DISKA_UUID
[root@nebula ~]# sudo mount -t ext4 /dev/diskB /mnt/disks/$DISKB_UUID
[root@nebula ~]# echo UUID=`sudo blkid -s UUID -o value /dev/diskA` /mnt/disks/$DISKA_UUID ext4 defaults 0 2 | sudo tee -a /etc/fstab
[root@nebula ~]# echo UUID=`sudo blkid -s UUID -o value /dev/diskB` /mnt/disks/$DISKB_UUID ext4 defaults 0 2 | sudo tee -a /etc/fstab部署本地存储卷插件
[root@nebula ~]# curl https://github.com/kubernetes-sigs/sig-storage-local-static-provisioner/archive/v2.3.3.zip
[root@nebula ~]# unzip v2.3.3.zip修改v2.3.3/helm/provisioner/values.yaml文件。
#
# Common options.
#
common:
#
# Defines whether to generate service account and role bindings.
#
rbac: true
#
# Defines the namespace where provisioner runs
#
namespace: default
#
# Defines whether to create provisioner namespace
#
createNamespace: false
#
# Beta PV.NodeAffinity field is used by default. If running against pre-1.10
# k8s version, the `useAlphaAPI` flag must be enabled in the configMap.
#
useAlphaAPI: false
#
# Indicates if PVs should be dependents of the owner Node.
#
setPVOwnerRef: false
#
# Provisioner clean volumes in process by default. If set to true, provisioner
# will use Jobs to clean.
#
useJobForCleaning: false
#
# Provisioner name contains Node.UID by default. If set to true, the provisioner
# name will only use Node.Name.
#
useNodeNameOnly: false
#
# Resync period in reflectors will be random between minResyncPeriod and
# 2*minResyncPeriod. Default: 5m0s.
#
#minResyncPeriod: 5m0s
#
# Defines the name of configmap used by Provisioner
#
configMapName: "local-provisioner-config"
#
# Enables or disables Pod Security Policy creation and binding
#
podSecurityPolicy: false
#
# Configure storage classes.
#
classes:
- name: fast-disks # Defines name of storage classes.
# Path on the host where local volumes of this storage class are mounted
# under.
hostDir: /mnt/fast-disks
# Optionally specify mount path of local volumes. By default, we use same
# path as hostDir in container.
# mountDir: /mnt/fast-disks
# The volume mode of created PersistentVolume object. Default to Filesystem
# if not specified.
volumeMode: Filesystem
# Filesystem type to mount.
# It applies only when the source path is a block device,
# and desire volume mode is Filesystem.
# Must be a filesystem type supported by the host operating system.
fsType: ext4
blockCleanerCommand:
# Do a quick reset of the block device during its cleanup.
# - "/scripts/quick_reset.sh"
# or use dd to zero out block dev in two iterations by uncommenting these lines
# - "/scripts/dd_zero.sh"
# - "2"
# or run shred utility for 2 iteration.s
- "/scripts/shred.sh"
- "2"
# or blkdiscard utility by uncommenting the line below.
# - "/scripts/blkdiscard.sh"
# Uncomment to create storage class object with default configuration.
# storageClass: true
# Uncomment to create storage class object and configure it.
# storageClass:
# reclaimPolicy: Delete # Available reclaim policies: Delete/Retain, defaults: Delete.
# isDefaultClass: true # set as default class
#
# Configure DaemonSet for provisioner.
#
daemonset:
#
# Defines the name of a Provisioner
#
name: "local-volume-provisioner"
#
# Defines Provisioner's image name including container registry.
#
image: quay.io/external_storage/local-volume-provisioner:v2.3.3
#
# Defines Image download policy, see kubernetes documentation for available values.
#
#imagePullPolicy: Always
#
# Defines a name of the service account which Provisioner will use to communicate with API server.
#
serviceAccount: local-storage-admin
#
# Defines a name of the Pod Priority Class to use with the Provisioner DaemonSet
#
# Note that if you want to make it critical, specify "system-cluster-critical"
# or "system-node-critical" and deploy in kube-system namespace.
# Ref: https://k8s.io/docs/tasks/administer-cluster/guaranteed-scheduling-critical-addon-pods/#marking-pod-as-critical
#
#priorityClassName: system-node-critical
# If configured, nodeSelector will add a nodeSelector field to the DaemonSet PodSpec.
#
# NodeSelector constraint for local-volume-provisioner scheduling to nodes.
# Ref: https://kubernetes.io/docs/concepts/configuration/assign-pod-node/#nodeselector
nodeSelector: {}
#
# If configured KubeConfigEnv will (optionally) specify the location of kubeconfig file on the node.
# kubeConfigEnv: KUBECONFIG
#
# List of node labels to be copied to the PVs created by the provisioner in a format:
#
# nodeLabels:
# - failure-domain.beta.kubernetes.io/zone
# - failure-domain.beta.kubernetes.io/region
#
# If configured, tolerations will add a toleration field to the DaemonSet PodSpec.
#
# Node tolerations for local-volume-provisioner scheduling to nodes with taints.
# Ref: https://kubernetes.io/docs/concepts/configuration/taint-and-toleration/
tolerations: []
#
# If configured, resources will set the requests/limits field to the Daemonset PodSpec.
# Ref: https://kubernetes.io/docs/concepts/configuration/manage-compute-resources-container/
resources: {}
#
# Configure Prometheus monitoring
#
prometheus:
operator:
## Are you using Prometheus Operator?
enabled: false
serviceMonitor:
## Interval at which Prometheus scrapes the provisioner
interval: 10s
# Namespace Prometheus is installed in
namespace: monitoring
## Defaults to what is used if you follow CoreOS [Prometheus Install Instructions](https://github.com/coreos/prometheus-operator/tree/master/helm#tldr)
## [Prometheus Selector Label](https://github.com/coreos/prometheus-operator/blob/master/helm/prometheus/templates/prometheus.yaml#L65)
## [Kube Prometheus Selector Label](https://github.com/coreos/prometheus-operator/blob/master/helm/kube-prometheus/values.yaml#L298)
selector:
prometheus: kube-prometheus修改hostDir: /mnt/fast-disks并# storageClass: true以hostDir: /mnt/disks和storageClass: true分别，然后运行：
# Installing
[root@nebula ~]# helm install local-static-provisioner v2.3.3/helm/provisioner
# List local-static-provisioner deployment
[root@nebula ~]# helm list部署Nebula Graph集群
下载NebulaHelm图包
# Downloading nebula
[root@nebula ~]# wget https://github.com/vesoft-inc/nebula/archive/master.zip
# Unzip
[root@nebula ~]# unzip master.zipKubernetes从节点打标签
以下是Kubernetes节点的列表。我们需要设置工作节点的调度标签。我们可以为192.168.0.2，192.168.0.3，192.168.0.4节点打上nebula: "yes"的标签。
| 服务器IP | kubernetes角色 | 节点名称 |
|---|---|---|
| 192.168.0.1 | master | 192.168.0.1 |
| 192.168.0.2 | worker | 192.168.0.2 |
| 192.168.0.3 | worker | 192.168.0.3 |
| 192.168.0.4 | worker | 192.168.0.4 |
具体操作如下：
[root@nebula ~]# kubectl label node 192.168.0.2 nebula="yes" --overwrite
[root@nebula ~]# kubectl label node 192.168.0.3 nebula="yes" --overwrite
[root@nebula ~]# kubectl label node 192.168.
### Deploying Ingress-controller on one Node修改Nebula Helm chart的默认值
以下是Nebula helm-chart 的目录列表：
master/kubernetes/
└── helm
├── Chart.yaml
├── templates
│ ├── configmap.yaml
│ ├── deployment.yaml
│ ├── _helpers.tpl
│ ├── ingress-configmap.yaml\
│ ├── NOTES.txt
│ ├── pdb.yaml
│ ├── service.yaml
│ └── statefulset.yaml
└── values.yaml
2 directories, 10 files我们需要调整yaml文件中MetadHosts的值master/kubernetes/values.yaml，并将IP列表替换为我们上文k8s worker的IP。
MetadHosts:
- 192.168.0.2:44500
- 192.168.0.3:44500
- 192.168.0.4:44500通过Helm安装Nebula
# Installing
[root@nebula ~]# helm install nebula master/kubernetes/helm
# Checking
[root@nebula ~]# helm status nebula
# Checking nebula deployment on the k8s cluster
[root@nebula ~]# kubectl get pod | grep nebula
nebula-graphd-579d89c958-g2j2c 1/1 Running 0 1m
nebula-graphd-579d89c958-p7829 1/1 Running 0 1m
nebula-graphd-579d89c958-q74zx 1/1 Running 0 1m
nebula-metad-0 1/1 Running 0 1m
nebula-metad-1 1/1 Running 0 1m
nebula-metad-2 1/1 Running 0 1m
nebula-storaged-0 1/1 Running 0 1m
nebula-storaged-1 1/1 Running 0 1m
nebula-storaged-2 1/1 Running 0 1m部署入口控制器(ingress-controller)
入口控制器是Kubernetes的附加组件之一。Kubernetes通过入口控制器向用户公开内部部署的服务。入口控制器还提供负载均衡功能，可以将外部访问分配给k8s中应用程序的不同副本。
选择要部署Ingress控制器的节点
[root@nebula ~]# kubectl get node
NAME STATUS ROLES AGE VERSION
192.168.0.1 Ready master 82d v1.16.1
192.168.0.2 Ready 82d v1.16.1
192.168.0.3 Ready 82d v1.16.1
192.168.0.4 Ready 82d v1.16.1
[root@nebula ~]# kubectl label node 192.168.0.4 ingress=yes 编辑ingress-nginx.yaml部署文件。
apiVersion: v1
kind: Namespace
metadata:
name: ingress-nginx
labels:
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
---
kind: ConfigMap
apiVersion: v1
metadata:
name: nginx-configuration
namespace: ingress-nginx
labels:
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
---
kind: ConfigMap
apiVersion: v1
metadata:
name: tcp-services
namespace: ingress-nginx
labels:
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
---
kind: ConfigMap
apiVersion: v1
metadata:
name: udp-services
namespace: ingress-nginx
labels:
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
---
apiVersion: v1
kind: ServiceAccount
metadata:
name: nginx-ingress-serviceaccount
namespace: ingress-nginx
labels:
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRole
metadata:
name: nginx-ingress-clusterrole
labels:
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
rules:
- apiGroups:
- ""
resources:
- configmaps
- endpoints
- nodes
- pods
- secrets
verbs:
- list
- watch
- apiGroups:
- ""
resources:
- nodes
verbs:
- get
- apiGroups:
- ""
resources:
- services
verbs:
- get
- list
- watch
- apiGroups:
- "extensions"
- "networking.k8s.io"
resources:
- ingresses
verbs:
- get
- list
- watch
- apiGroups:
- ""
resources:
- events
verbs:
- create
- patch
- apiGroups:
- "extensions"
- "networking.k8s.io"
resources:
- ingresses/status
verbs:
- update
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: Role
metadata:
name: nginx-ingress-role
namespace: ingress-nginx
labels:
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
rules:
- apiGroups:
- ""
resources:
- configmaps
- pods
- secrets
- namespaces
verbs:
- get
- apiGroups:
- ""
resources:
- configmaps
resourceNames:
# Defaults to "-"
# Here: "-"
# This has to be adapted if you change either parameter
# when launching the nginx-ingress-controller.
- "ingress-controller-leader-nginx"
verbs:
- get
- update
- apiGroups:
- ""
resources:
- configmaps
verbs:
- create
- apiGroups:
- ""
resources:
- endpoints
verbs:
- get
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: RoleBinding
metadata:
name: nginx-ingress-role-nisa-binding
namespace: ingress-nginx
labels:
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: Role
name: nginx-ingress-role
subjects:
- kind: ServiceAccount
name: nginx-ingress-serviceaccount
namespace: ingress-nginx
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:
name: nginx-ingress-clusterrole-nisa-binding
labels:
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: nginx-ingress-clusterrole
subjects:
- kind: ServiceAccount
name: nginx-ingress-serviceaccount
namespace: ingress-nginx
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
name: nginx-ingress-controller
namespace: ingress-nginx
labels:
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
spec:
selector:
matchLabels:
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
template:
metadata:
labels:
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
annotations:
prometheus.io/port: "10254"
prometheus.io/scrape: "true"
spec:
hostNetwork: true
tolerations:
- key: "node-role.kubernetes.io/master"
operator: "Exists"
effect: "NoSchedule"
affinity:
podAntiAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
- labelSelector:
matchExpressions:
- key: app.kubernetes.io/name
operator: In
values:
- ingress-nginx
topologyKey: "ingress-nginx.kubernetes.io/master"
nodeSelector:
ingress: "yes"
serviceAccountName: nginx-ingress-serviceaccount
containers:
- name: nginx-ingress-controller
image: quay.io/kubernetes-ingress-controller/nginx-ingress-controller-amd64:0.26.1
args:
- /nginx-ingress-controller
- --configmap=$(POD_NAMESPACE)/nginx-configuration
- --tcp-services-configmap=default/graphd-services
- --udp-services-configmap=$(POD_NAMESPACE)/udp-services
- --publish-service=$(POD_NAMESPACE)/ingress-nginx
- --annotations-prefix=nginx.ingress.kubernetes.io
- --http-port=8000
securityContext:
allowPrivilegeEscalation: true
capabilities:
drop:
- ALL
add:
- NET_BIND_SERVICE
# www-data -> 33
runAsUser: 33
env:
- name: POD_NAME
valueFrom:
fieldRef:
fieldPath: metadata.name
- name: POD_NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace
ports:
- name: http
containerPort: 80
- name: https
containerPort: 443
livenessProbe:
failureThreshold: 3
httpGet:
path: /healthz
port: 10254
scheme: HTTP
initialDelaySeconds: 10
periodSeconds: 10
successThreshold: 1
timeoutSeconds: 10
readinessProbe:
failureThreshold: 3
httpGet:
path: /healthz
port: 10254
scheme: HTTP
periodSeconds: 10
successThreshold: 1
timeoutSeconds: 10 部署ingress-nginx。
# Deployment
[root@nebula ~]# kubectl create -f ingress-nginx.yaml
# View deployment
[root@nebula ~]# kubectl get pod -n ingress-nginx
NAME READY STATUS RESTARTS AGE
nginx-ingress-controller-mmms7 1/1 Running 2 1m在Kubernetes中访问Nebula Graph集群
查看ingress-nginx位于哪个节点：
[root@nebula ~]# kubectl get node -l ingress=yes -owide
NAME STATUS ROLES AGE VERSION INTERNAL-IP EXTERNAL-IP OS-IMAGE KERNEL-VERSION CONTAINER-RUNTIME
nebula.node23 Ready 1d v1.16.1 192.168.8.23 CentOS Linux 7 (Core) 7.6.1810.el7.x86_64 docker://19.3.3 访问 Nebula Graph 集群：
[root@nebula ~]# docker run --rm -ti --net=host vesoft/nebula-console:nightly --addr=192.168.8.23 --port=3699常问问题
如何部署Kubernetes集群
请参考--高可用Kubernetes集群部署的官方文档。
你也可以参考使用Minikube安装Kubernetes来部署本地Kubernetes集群。
如何修改Nebula Graph集群参数？
使用helm install时，可以使用--set 覆盖中的默认变量values.yaml。有关详细信息，请参阅Helm。
如何观察Nebula 集群状态？
你可以使用kubectl get pod | grep nebula命令或通过kubernetes仪表板。
如何使用其他磁盘类型？
请参考存储文档。
译文链接：https://dzone.com/articles/how-to-deploy-nebula-graph-on-kubernetes-a-step-by