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OpenEBS and Nuodb

Introduction#

NuoDB’s distributed SQL database combines the elastic scale and continuous availability of the cloud with the transactional consistency and durability that databases of record demand. NuoDB is deployed usually as a StatefulSet on Kubernetes and requires persistent storage for each instance of NuoDB StorageManager instance. OpenEBS provides persistent volumes on the fly when StorageManagers are scaled up.

Advantages of using OpenEBS for NuoDB database:

  • No need to manage the local disks, they are managed by OpenEBS
  • Large size PVs can be provisioned by OpenEBS and NuoDB
  • Start with small storage and add disks as needed on the fly. Sometimes NuoDB instances are scaled up because of capacity on the nodes. With OpenEBS persistent volumes, capacity can be thin provisioned and disks can be added to OpenEBS on the fly without disruption of service
  • If required, take backup of the NuoDB data periodically and back them up to S3 or any object storage so that restoration of the same data is possible to the same or any other Kubernetes cluster

Note: NuoDB can be deployed both as deployment or as statefulset. When NuoDB deployed as statefulset, you don't need to replicate the data again at OpenEBS level. When NuoDB is deployed as deployment, consider 3 OpenEBS replicas, choose the StorageClass accordingly.

Deployment model#

OpenEBS and NuoDB

Configuration workflow#

  1. Install OpenEBS

    If OpenEBS is not installed in your K8s cluster, this can done from here. If OpenEBS is already installed, go to the next step.

  2. Configure cStor Pool

    After OpenEBS installation, cStor pool has to be configured. If cStor Pool is not configured in your OpenEBS cluster, this can be done from here. Sample YAML named openebs-config.yaml for configuring cStor Pool is provided in the Configuration details below. During cStor Pool creation, make sure that the maxPools parameter is set to >=3. If cStor pool is already configured, go to the next step.

  3. Create Storage Class

    You must configure a StorageClass to provision cStor volume on given cStor pool. StorageClass is the interface through which most of the OpenEBS storage policies are defined. In this solution we are using a StorageClass to consume the cStor Pool which is created using external disks attached on the Nodes. Since NuoDB is a StatefulSet application, it requires only single storage replica. So cStor volume replicaCount is =1. Sample YAML named openebs-sc-disk.yaml to consume cStor pool with cStor volume replica count as 1 is provided in the configuration details below.

  4. Download the YAML spec files from OpenEBS litmus repository.

    wget https://raw.githubusercontent.com/openebs/litmus/master/apps/nuodb/deployers/nuodb.yaml
    wget https://raw.githubusercontent.com/openebs/litmus/master/apps/nuodb/deployers/nuodb-sm.yaml
    wget https://raw.githubusercontent.com/openebs/litmus/master/apps/nuodb/deployers/nuodb-te.yaml
  5. Edit the above YAML spec files and update them with correct StorageClass. For example, replace openebs-cstor-sparse with openebs-cstor-disk

  6. Launch and test NuoDB

    Create a namespace called testns and apply following YAML files to deploy NuoDB application. Sample YAML files are provided in the Configuration details below.

    kubectl apply -f nuodb.yaml -n testns
    kubectl apply -f nuodb-sm.yaml -n testns
    kubectl apply -f nuodb-te.yaml -n testns

Reference at openebs.ci#

Deployment YAML spec files for NuoDB and OpenEBS resources are found here

OpenEBS-CI dashboard of NuoDB

Live access to NuoDB dashboard

Post deployment Operations#

Monitor OpenEBS Volume size

It is not seamless to increase the cStor volume size (refer to the roadmap item). Hence, it is recommended that sufficient size is allocated during the initial configuration.

Monitor cStor Pool size

As in most cases, cStor pool may not be dedicated to just NuoDB database alone. It is recommended to watch the pool capacity and add more disks to the pool before it hits 80% threshold. See cStorPool metrics

Configuration details#

openebs-config.yaml

#Use the following YAMLs to create a cStor Storage Pool.
# and associated storage class.
apiVersion: openebs.io/v1alpha1
kind: StoragePoolClaim
metadata:
name: cstor-disk
spec:
name: cstor-disk
type: disk
poolSpec:
poolType: striped
# NOTE - Appropriate disks need to be fetched using `kubectl get blockdevices -n openebs`
# `Block devices` is a custom resource supported by OpenEBS with `node-disk-manager`
# as the disk operator
# Replace the following with actual disk CRs from your cluster `kubectl get blockdevices -n openebs`
# Uncomment the below lines after updating the actual disk names.
blockDevices:
blockDeviceList:
# Replace the following with actual disk CRs from your cluster from `kubectl get blockdevices -n openebs`
# - blockdevice-69cdfd958dcce3025ed1ff02b936d9b4
# - blockdevice-891ad1b581591ae6b54a36b5526550a2
# - blockdevice-ceaab442d802ca6aae20c36d20859a0b
---

openebs-sc-disk.yaml

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
name: openebs-cstor-disk
annotations:
openebs.io/cas-type: cstor
cas.openebs.io/config: |
- name: StoragePoolClaim
value: "cstor-disk"
- name: ReplicaCount
value: "1"
provisioner: openebs.io/provisioner-iscsi
reclaimPolicy: Delete
---

nuodb.yaml

---
apiVersion: v1
kind: Service
metadata:
annotations:
description: |
Headless service permitting us to retrieve DNS A records that point directly to the pods backing the service.
"service.alpha.kubernetes.io/tolerate-unready-endpoints": "true"
name: domain
labels:
app: nuodb
group: nuodb
spec:
clusterIP: None
ports:
- { name: 8888-tcp, port: 8888, protocol: TCP, targetPort: 8888 }
- { name: 48004-tcp, port: 48004, protocol: TCP, targetPort: 48004 }
- { name: 48005-tcp, port: 48005, protocol: TCP, targetPort: 48005 }
selector:
dns: domain
sessionAffinity: None
type: ClusterIP
status:
loadBalancer: {}
---
apiVersion: v1
kind: Service
metadata:
annotations:
description: "Service (and load-balancer) for Admin pods."
labels:
app: nuodb
group: nuodb
name: admin
spec:
ports:
- { name: 8888-tcp, port: 8888, protocol: TCP, targetPort: 8888 }
- { name: 48004-tcp, port: 48004, protocol: TCP, targetPort: 48004 }
- { name: 48005-tcp, port: 48005, protocol: TCP, targetPort: 48005 }
selector:
app: admin
sessionAffinity: None
type: LoadBalancer
status:
loadBalancer: {}
---
apiVersion: apps/v1beta1
kind: StatefulSet
metadata:
name: admin
labels:
app: nuodb
group: nuodb
spec:
serviceName: domain
replicas: 1
selector:
matchLabels:
affinity: admin
template:
metadata:
labels:
dns: domain
app: admin
affinity: admin
spec:
securityContext:
runAsUser: 0
fsGroup: 0
containers:
- name: admin
image: nuodb/nuodb-ce:latest
imagePullPolicy: IfNotPresent
ports:
- { containerPort: 8888, protocol: TCP }
- { containerPort: 48004, protocol: TCP }
- { containerPort: 48005, protocol: TCP }
resources:
requests:
memory: "512Mi"
cpu: "0.5"
limits:
memory: "1024Mi"
cpu: "1"
env:
- name: NODE_NAME
valueFrom:
fieldRef:
fieldPath: spec.nodeName
- name: POD_NAME
valueFrom:
fieldRef:
fieldPath: metadata.name
- name: NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace
- { name: NUODB_DOMAIN_ENTRYPOINT, value: "admin-0.domain" }
- { name: NUODB_ALT_ADDRESS, value: "$(POD_NAME).domain.testns.svc" }
- { name: NUODB_VARDIR, value: "/var/opt/nuodb/$(POD_NAME).testns" }
args: [ "nuoadmin" ]
livenessProbe:
initialDelaySeconds: 30
periodSeconds: 15
tcpSocket:
port: 8888
readinessProbe:
initialDelaySeconds: 30
periodSeconds: 15
exec:
command: [ "nuodocker", "check", "servers" ]
volumeMounts:
- name: raftlog
mountPath: /var/opt/nuodb
- name: log-volume
mountPath: /var/log/nuodb
volumes:
- name: log-volume
emptyDir: {}
volumeClaimTemplates:
- metadata:
name: raftlog
annotations:
volume.beta.kubernetes.io/storage-class: openebs-cstor-sparse
spec:
accessModes: [ "ReadWriteOnce" ]
resources:
requests:
storage: 5G
---
apiVersion: v1
kind: Service
metadata:
annotations:
description: "Service for redirect."
labels:
app: insights
group: nuodb
name: insights-server
spec:
ports:
- { name: 8080-tcp, port: 8080, protocol: TCP, targetPort: 8080 }
selector:
app: insights
group: nuodb
sessionAffinity: None
type: LoadBalancer
status:
loadBalancer: {}
---
apiVersion: v1
kind: ConfigMap
metadata:
annotations:
description: "Config map for metrics input and insights output"
name: insights-configmap
labels:
group: nuodb
data:
nuoca.yml.template: |
---
NUOCA_LOGFILE: /var/log/nuodb/nuoca.log
INPUT_PLUGINS:
- NuoAdminNuoMon:
description : Collection from NuoDB engines
nuocaCollectionName: NuoMon
api_server: https://domain:8888
client_key: /etc/nuodb/keys/nuocmd.pem
OUTPUT_PLUGINS:
- RestClient:
url: ${INSIGHTS_INGEST_URL}
nuoinsights: |
#!/bin/bash
. ${NUODB_HOME}/etc/nuodb_setup.sh
: ${NUOCMD_API_SERVER:=https://domain:8888}
SCRIPT=$(cat <<EOF
from BaseHTTPServer import BaseHTTPRequestHandler,HTTPServer
from nuoca import NuoCA as nuoca
import nuodb_mgmt
PORT_NUMBER = 8080
def get_insights_dashboard():
conn = nuodb_mgmt.AdminConnection('${NUOCMD_API_SERVER}', '/etc/nuodb/keys/nuocmd.pem')
metadata = nuoca.get_insights_metadata(conn)
return metadata.get(nuoca.INSIGHTS_DASHBOARD_KEY,None)
#ingest_url = metadata[nuoca.INSIGHTS_URL_KEY]
#subscriber_id = metadata[nuoca.INSIGHTS_ID_KEY]
#return ingest_url[:-6] + subscriber_id
class myHandler(BaseHTTPRequestHandler):
def do_GET(self):
new_path = get_insights_dashboard()
if new_path and new_path != "None":
self.send_response(307)
self.send_header('Location', new_path)
self.end_headers()
else:
self.send_response(404)
self.end_headers()
return
try:
server = HTTPServer(('', PORT_NUMBER), myHandler)
print 'Started httpserver on port ' , PORT_NUMBER
#Wait forever for incoming http requests
server.serve_forever()
except KeyboardInterrupt:
print '^C received, shutting down the web server'
server.socket.close()
EOF
)
export PYTHONPATH=/opt/nuodb/drivers/pynuoadmin
exec /opt/nuodb/etc/python/nuopython -c "${SCRIPT}"
---
apiVersion: v1
kind: Pod
metadata:
name: nuodb-insights
labels:
app: insights
group: nuodb
spec:
initContainers:
- name: optin
image: nuodb/nuodb-ce:latest
imagePullPolicy: IfNotPresent
args:
- "/bin/sh"
- "-c"
- "[ \"${OPT_IN}\" == \"true\" ] && nuoca enable insights --connect-timeout 300 || nuoca disable insights --connect-timeout 300"
env:
- { name: NUOCMD_API_SERVER , value: "https://domain:8888" }
containers:
- name: insights
image: nuodb/nuodb-ce:latest
imagePullPolicy: IfNotPresent
args: [ "nuoca", "start" , "nuoca", "--insights" ]
env:
- { name: NUOCMD_API_SERVER , value: "https://domain:8888" }
volumeMounts:
- name: log-volume
mountPath: /var/log/nuodb
- name: config-insights
mountPath: /etc/nuodb/nuoca.yml.template
subPath: nuoca.yml.template
- name: insights-server
image: nuodb/nuodb-ce:latest
imagePullPolicy: IfNotPresent
args: [ "nuoinsights" ]
ports:
- { name: 8080-tcp, containerPort: 8080, protocol: TCP }
env:
- { name: NUOCMD_API_SERVER , value: "https://domain:8888" }
volumeMounts:
- name: log-volume
mountPath: /var/log/nuodb
- name: nuoinsights
mountPath: /usr/local/bin/nuoinsights
subPath: nuoinsights
volumes:
- name: log-volume
emptyDir: {}
- name: config-insights
configMap:
name: insights-configmap
- name: nuoinsights
configMap:
name: insights-configmap
defaultMode: 0754

nuodb-sm.yaml

---
apiVersion: apps/v1beta1
kind: StatefulSet
metadata:
name: sm
labels:
app: nuodb
group: nuodb
spec:
serviceName: sm
replicas: 1
selector:
matchLabels:
nodetype: sm
database: nuodb
app: sm
group: nuodb
podManagementPolicy: Parallel
template:
metadata:
labels:
nodetype: sm
database: nuodb
app: sm
group: nuodb
spec:
securityContext:
runAsUser: 0
fsGroup: 0
containers:
- name: sm
image: nuodb/nuodb-ce:latest
imagePullPolicy: IfNotPresent
args: [ "nuosm", "--servers-ready-timeout", "300" ]
env:
- name: NODE_NAME
valueFrom:
fieldRef:
fieldPath: spec.nodeName
- name: POD_NAME
valueFrom:
fieldRef:
fieldPath: metadata.name
- name: NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace
- { name: DB_NAME, value: "nuodb"}
- { name: DB_USER, value: "dba"}
- { name: DB_PASSWORD, value: "goalie"}
- { name: NUOCMD_API_SERVER, value: "admin.testns.svc:8888"}
- { name: PEER_ADDRESS, value: "admin.testns.svc" }
- { name: NUODB_OPTIONS, value: "mem 1g" }
ports:
- containerPort: 48006
protocol: TCP
resources:
requests:
memory: "1Gi"
cpu: "200m"
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
volumeMounts:
- mountPath: /var/opt/nuodb/archive
name: archive
volumeClaimTemplates:
- metadata:
name: archive
annotations:
volume.beta.kubernetes.io/storage-class: openebs-cstor-sparse
spec:
accessModes: [ "ReadWriteOnce" ]
resources:
requests:
storage: 5G

nuodb-te.yaml

---
apiVersion: apps/v1beta1
kind: Deployment
metadata:
name: te
labels:
app: nuodb
group: nuodb
deploymentconfig: te
spec:
replicas: 1
template:
metadata:
labels:
app: te
deploymentconfig: te
database: nuodb
nodetype: te
spec:
containers:
-
name: te
image: nuodb/nuodb-ce:latest
imagePullPolicy: IfNotPresent
env:
- name: NODE_NAME
valueFrom:
fieldRef:
fieldPath: spec.nodeName
- name: POD_NAME
valueFrom:
fieldRef:
fieldPath: metadata.name
- name: NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace
- { name: DB_NAME, value: "nuodb" }
- { name: NUOCMD_API_SERVER, value: "admin.testns.svc:8888"}
- { name: PEER_ADDRESS, value: "admin.testns.svc" }
- { name: NUODB_LABELS, value: "" }
- { name: NUODB_OPTIONS, value: "mem 1g" }
args: [ "nuote", "--servers-ready-timeout", "300", "--database-created-timeout", "300" ]
ports:
- containerPort: 48006
protocol: TCP
resources:
requests:
memory: "1Gi"
cpu: "200m"
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
volumeMounts:
- name: logdir
mountPath: /var/log/nuodb
volumes:
- name: logdir
emptyDir: {}

See Also:#

OpenEBS architecture OpenEBS use cases cStor pools overview

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