New to KubeDB? Please start here.
MongoDB
What is MongoDB
MongoDB
is a Kubernetes Custom Resource Definitions
(CRD). It provides declarative configuration for MongoDB in a Kubernetes native way. You only need to describe the desired database configuration in a MongoDB object, and the KubeDB operator will create Kubernetes objects in the desired state for you.
MongoDB Spec
As with all other Kubernetes objects, a MongoDB needs apiVersion
, kind
, and metadata
fields. It also needs a .spec
section. Below is an example MongoDB object.
apiVersion: kubedb.com/v1
kind: MongoDB
metadata:
name: mgo1
namespace: demo
spec:
autoOps:
disabled: true
version: "4.4.26"
replicas: 3
authSecret:
name: mgo1-auth
externallyManaged: false
replicaSet:
name: rs0
shardTopology:
configServer:
podTemplate: {}
replicas: 3
storage:
resources:
requests:
storage: 1Gi
storageClassName: standard
mongos:
podTemplate: {}
replicas: 2
shard:
podTemplate: {}
replicas: 3
shards: 3
storage:
resources:
requests:
storage: 1Gi
storageClassName: standard
sslMode: requireSSL
tls:
issuerRef:
name: mongo-ca-issuer
kind: Issuer
apiGroup: "cert-manager.io"
certificates:
- alias: client
subject:
organizations:
- kubedb
emailAddresses:
- [email protected]
- alias: server
subject:
organizations:
- kubedb
emailAddresses:
- [email protected]
clusterAuthMode: x509
storageType: "Durable"
storageEngine: wiredTiger
storage:
storageClassName: "standard"
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
ephemeralStorage:
medium: "Memory"
sizeLimit: 500Mi
init:
script:
configMap:
name: mg-init-script
monitor:
agent: prometheus.io/operator
prometheus:
serviceMonitor:
labels:
app: kubedb
interval: 10s
configSecret:
name: mg-custom-config
podTemplate:
metadata:
annotations:
passMe: ToDatabasePod
labels:
thisLabel: willGoToPod
controller:
annotations:
passMe: ToPetSet
labels:
thisLabel: willGoToSts
spec:
serviceAccountName: my-service-account
schedulerName: my-scheduler
nodeSelector:
disktype: ssd
imagePullSecrets:
- name: myregistrykey
containers:
- name: mongo
args:
- --maxConns=100
env:
- name: MONGO_INITDB_DATABASE
value: myDB
resources:
requests:
memory: "64Mi"
cpu: "250m"
limits:
memory: "128Mi"
cpu: "500m"
- name: replication-mode-detector
resources:
requests:
cpu: "300m"
memory: 500Mi
securityContext:
runAsUser: 1001
serviceTemplates:
- alias: primary
spec:
type: NodePort
ports:
- name: primary
port: 27017
nodePort: 300006
deletionPolicy: Halt
halted: false
arbiter:
podTemplate:
spec:
resources:
requests:
cpu: "200m"
memory: "200Mi"
configSecret:
name: another-config
allowedSchemas:
namespaces:
from: Selector
selector:
matchExpressions:
- {key: kubernetes.io/metadata.name, operator: In, values: [dev]}
selector:
matchLabels:
"schema.kubedb.com": "mongo"
healthChecker:
periodSeconds: 15
timeoutSeconds: 10
failureThreshold: 2
disableWriteCheck: false
spec.autoOps
AutoOps is an optional field to control the generation of versionUpdate & TLS-related recommendations.
spec.version
spec.version
is a required field specifying the name of the MongoDBVersion crd where the docker images are specified. Currently, when you install KubeDB, it creates the following MongoDBVersion
resources,
3.4.17-v1
,3.4.22-v1
3.6.13-v1
,4.4.26
,4.0.3-v1
,4.4.26
,4.0.11-v1
,4.1.4-v1
,4.1.7-v3
,4.4.26
4.4.26
,4.4.26
5.0.2
,5.0.3
percona-3.6.18
percona-4.0.10
,percona-4.2.7
,percona-4.4.10
spec.replicas
spec.replicas
the number of members(primary & secondary) in mongodb replicaset.
If spec.shardTopology
is set, then spec.replicas
needs to be empty. Instead use spec.shardTopology.<shard/configServer/mongos>.replicas
If both spec.replicaset
and spec.shardTopology
is not set, then spec.replicas
can be value 1
.
KubeDB uses PodDisruptionBudget
to ensure that majority of these replicas are available during voluntary disruptions so that quorum is maintained.
spec.authSecret
spec.authSecret
is an optional field that points to a Secret used to hold credentials for mongodb
superuser. If not set, KubeDB operator creates a new Secret {mongodb-object-name}-auth
for storing the password for mongodb
superuser for each MongoDB object.
We can use this field in 3 mode.
- Using an external secret. In this case, You need to create an auth secret first with required fields, then specify the secret name when creating the MongoDB object using
spec.authSecret.name
& setspec.authSecret.externallyManaged
to true.
authSecret:
name: <your-created-auth-secret-name>
externallyManaged: true
- Specifying the secret name only. In this case, You need to specify the secret name when creating the MongoDB object using
spec.authSecret.name
.externallyManaged
is by default false.
authSecret:
name: <intended-auth-secret-name>
- Let KubeDB do everything for you. In this case, no work for you.
AuthSecret contains a user
key and a password
key which contains the username
and password
respectively for mongodb
superuser.
Example:
$ kubectl create secret generic mgo1-auth -n demo \
--from-literal=username=jhon-doe \
--from-literal=password=6q8u_2jMOW-OOZXk
secret "mgo1-auth" created
apiVersion: v1
data:
password: NnE4dV8yak1PVy1PT1pYaw==
username: amhvbi1kb2U=
kind: Secret
metadata:
name: mgo1-auth
namespace: demo
type: Opaque
Secrets provided by users are not managed by KubeDB, and therefore, won’t be modified or garbage collected by the KubeDB operator (version 0.13.0 and higher).
spec.replicaSet
spec.replicaSet
represents the configuration for replicaset. When spec.replicaSet
is set, KubeDB will deploy a mongodb replicaset where number of replicaset member is spec.replicas.
name
denotes the name of mongodb replicaset. NB. Ifspec.shardTopology
is set, thenspec.replicaset
needs to be empty.
spec.keyFileSecret
keyFileSecret.name
denotes the name of the secret that contains the key.txt
, which provides the security between replicaset members using internal authentication. See Keyfile Authentication for more information.
It will make impact only if the ClusterAuthMode is keyFile
or sendKeyFile
.
spec.shardTopology
spec.shardTopology
represents the topology configuration for sharding.
Available configurable fields:
- shard
- configServer
- mongos
When spec.shardTopology
is set, the following fields needs to be empty, otherwise validating webhook will throw error.
spec.replicas
spec.podTemplate
spec.configSecret
spec.storage
spec.ephemeralStorage
KubeDB uses PodDisruptionBudget
to ensure that majority of the replicas of these shard components are available during voluntary disruptions so that quorum and data integrity is maintained.
spec.shardTopology.shard
shard
represents configuration for Shard component of mongodb.
Available configurable fields:
shards
represents number of shards for a mongodb deployment. Each shard is deployed as a replicaset.replicas
represents number of replicas of each shard replicaset.prefix
represents the prefix of each shard node.configSecret
is an optional field to provide custom configuration file for shards (i.e. mongod.cnf). If specified, this file will be used as configuration file otherwise a default configuration file will be used. See below to know about spec.configSecret in details.podTemplate
is an optional configuration for pods. See below to know about spec.podTemplate in details.storage
to specify pvc spec for each node of sharding. You can specify any StorageClass available in your cluster with appropriate resource requests. See below to know about spec.storage in details.ephemeralStorage
to specify the configuration of ephemeral storage type, If you want to use volatile temporary storage attached to your instances which is only present during the running lifetime of the instance.
spec.shardTopology.configServer
configServer
represents configuration for ConfigServer component of mongodb.
Available configurable fields:
replicas
represents number of replicas for configServer replicaset. Here, configServer is deployed as a replicaset of mongodb.prefix
represents the prefix of configServer nodes.configSecret
is an optional field to provide custom configuration file for config server (i.e mongod.cnf). If specified, this file will be used as configuration file otherwise a default configuration file will be used. See below to know about spec.configSecret in details.podTemplate
is an optional configuration for pods. See below to know about spec.podTemplate in details.storage
to specify pvc spec for each node of configServer. You can specify any StorageClass available in your cluster with appropriate resource requests. See below to know about spec.storage in details.ephemeralStorage
to specify the configuration of ephemeral storage type, If you want to use volatile temporary storage attached to your instances which is only present during the running lifetime of the instance.
spec.shardTopology.mongos
mongos
represents configuration for Mongos component of mongodb.
Available configurable fields:
replicas
represents number of replicas ofMongos
instance. Here, Mongos is deployed as stateless (deployment) instance.prefix
represents the prefix of mongos nodes.configSecret
is an optional field to provide custom configuration file for mongos (i.e. mongod.cnf). If specified, this file will be used as configuration file otherwise a default configuration file will be used. See below to know about spec.configSecret in details.podTemplate
is an optional configuration for pods. See below to know about spec.podTemplate in details.
spec.sslMode
Enables TLS/SSL or mixed TLS/SSL used for all network connections. The value of sslMode
field can be one of the following:
Value | Description |
---|---|
disabled | The server does not use TLS/SSL. |
allowSSL | Connections between servers do not use TLS/SSL. For incoming connections, the server accepts both TLS/SSL and non-TLS/non-SSL. |
preferSSL | Connections between servers use TLS/SSL. For incoming connections, the server accepts both TLS/SSL and non-TLS/non-SSL. |
requireSSL | The server uses and accepts only TLS/SSL encrypted connections. |
spec.tls
spec.tls
specifies the TLS/SSL configurations for the MongoDB. KubeDB uses cert-manager v1 api to provision and manage TLS certificates.
The following fields are configurable in the spec.tls
section:
issuerRef
is a reference to theIssuer
orClusterIssuer
CR of cert-manager that will be used byKubeDB
to generate necessary certificates.apiGroup
is the group name of the resource that is being referenced. Currently, the only supported value iscert-manager.io
.kind
is the type of resource that is being referenced. KubeDB supports bothIssuer
andClusterIssuer
as values for this field.name
is the name of the resource (Issuer
orClusterIssuer
) being referenced.
certificates
(optional) are a list of certificates used to configure the server and/or client certificate. It has the following fields:alias
represents the identifier of the certificate. It has the following possible value:server
is used for server certificate identification.client
is used for client certificate identification.metrics-exporter
is used for metrics exporter certificate identification.
secretName
(optional) specifies the k8s secret name that holds the certificates.This field is optional. If the user does not specify this field, the default secret name will be created in the following format:
<database-name>-<cert-alias>-cert
.subject
(optional) specifies anX.509
distinguished name. It has the following possible field,organizations
(optional) are the list of different organization names to be used on the Certificate.organizationalUnits
(optional) are the list of different organization unit name to be used on the Certificate.countries
(optional) are the list of country names to be used on the Certificate.localities
(optional) are the list of locality names to be used on the Certificate.provinces
(optional) are the list of province names to be used on the Certificate.streetAddresses
(optional) are the list of a street address to be used on the Certificate.postalCodes
(optional) are the list of postal code to be used on the Certificate.serialNumber
(optional) is a serial number to be used on the Certificate. You can find more details from Here
duration
(optional) is the period during which the certificate is valid.renewBefore
(optional) is a specifiable time before expiration duration.dnsNames
(optional) is a list of subject alt names to be used in the Certificate.ipAddresses
(optional) is a list of IP addresses to be used in the Certificate.uris
(optional) is a list of URI Subject Alternative Names to be set in the Certificate.emailAddresses
(optional) is a list of email Subject Alternative Names to be set in the Certificate.privateKey
(optional) specifies options to control private keys used for the Certificate.encoding
(optional) is the private key cryptography standards (PKCS) encoding for this certificate’s private key to be encoded in. If provided, allowed values are “pkcs1” and “pkcs8” standing for PKCS#1 and PKCS#8, respectively. It defaults to PKCS#1 if not specified.
spec.clusterAuthMode
The authentication mode used for cluster authentication. This option can have one of the following values:
Value | Description |
---|---|
keyFile | Use a keyfile for authentication. Accept only keyfiles. |
sendKeyFile | For rolling update purposes. Send a keyfile for authentication but can accept both keyfiles and x.509 certificates. |
sendX509 | For rolling update purposes. Send the x.509 certificate for authentication but can accept both keyfiles and x.509 certificates. |
x509 | Recommended. Send the x.509 certificate for authentication and accept only x.509 certificates. |
spec.storageType
spec.storageType
is an optional field that specifies the type of storage to use for database. It can be either Durable
or Ephemeral
. The default value of this field is Durable
. If Ephemeral
is used then KubeDB will create MongoDB database using emptyDir volume.
In this case, you don’t have to specify spec.storage
field. Specify spec.ephemeralStorage
spec instead.
spec.storageEngine
spec.storageEngine
is an optional field that specifies the type of storage engine is going to be used by mongodb. There are two types of storage engine, wiredTiger
and inMemory
. Default value of storage engine is wiredTiger
. inMemory
storage engine is only supported by the percona variant of mongodb, i.e. the version that has the percona-
prefix in the mongodb-version name.
spec.storage
Since 0.9.0-rc.0, If you set spec.storageType:
to Durable
, then spec.storage
is a required field that specifies the StorageClass of PVCs dynamically allocated to store data for the database. This storage spec will be passed to the PetSet created by KubeDB operator to run database pods. You can specify any StorageClass available in your cluster with appropriate resource requests.
spec.storage.storageClassName
is the name of the StorageClass used to provision PVCs. PVCs don’t necessarily have to request a class. A PVC with its storageClassName set equal to "" is always interpreted to be requesting a PV with no class, so it can only be bound to PVs with no class (no annotation or one set equal to “”). A PVC with no storageClassName is not quite the same and is treated differently by the cluster depending on whether the DefaultStorageClass admission plugin is turned on.spec.storage.accessModes
uses the same conventions as Kubernetes PVCs when requesting storage with specific access modes.spec.storage.resources
can be used to request specific quantities of storage. This follows the same resource model used by PVCs.
To learn how to configure spec.storage
, please visit the links below:
NB. If spec.shardTopology
is set, then spec.storage
needs to be empty. Instead use spec.shardTopology.<shard/configServer>.storage
spec.ephemeralStorage
Use this field to specify the configuration of ephemeral storage type, If you want to use volatile temporary storage attached to your instances which is only present during the running lifetime of the instance.
spec.ephemeralStorage.medium
refers to the name of the storage medium.spec.ephemeralStorage.sizeLimit
to specify the sizeLimit of the emptyDir volume.
For more details of these two fields, see EmptyDir struct
spec.init
spec.init
is an optional section that can be used to initialize a newly created MongoDB database. MongoDB databases can be initialized by Script.
Initialize from Snapshot
is still not supported.
Initialize via Script
To initialize a MongoDB database using a script (shell script, js script), set the spec.init.script
section when creating a MongoDB object. It will execute files alphabetically with extensions .sh
and .js
that are found in the repository. script must have the following information:
- VolumeSource: Where your script is loaded from.
Below is an example showing how a script from a configMap can be used to initialize a MongoDB database.
apiVersion: kubedb.com/v1
kind: MongoDB
metadata:
name: mgo1
namespace: demo
spec:
version: 4.4.26
init:
script:
configMap:
name: mongodb-init-script
In the above example, KubeDB operator will launch a Job to execute all js script of mongodb-init-script
in alphabetical order once PetSet pods are running. For more details tutorial on how to initialize from script, please visit here.
These are the fields of spec.init
which you can make use of :
spec.init.initialized
indicating that this database has been initialized or not.false
by default.spec.init.script.scriptPath
to specify where all the init scripts should be mounted.spec.init.script.<volumeSource>
as described in the above example. To see all the volumeSource options go to VolumeSource.spec.init.waitForInitialRestore
to tell the operator if it should wait for the initial restore process or not.
spec.monitor
MongoDB managed by KubeDB can be monitored with builtin-Prometheus and Prometheus operator out-of-the-box. To learn more,
spec.configSecret
spec.configSecret
is an optional field that allows users to provide custom configuration for MongoDB. You can provide the custom configuration in a secret, then you can specify the secret name spec.configSecret.name
.
Please note that, the secret key needs to be
mongod.conf
.
To learn more about how to use a custom configuration file see here.
NB. If spec.shardTopology
is set, then spec.configSecret
needs to be empty. Instead use spec.shardTopology.<shard/configServer/mongos>.configSecret
spec.podTemplate
KubeDB allows providing a template for database pod through spec.podTemplate
. KubeDB operator will pass the information provided in spec.podTemplate
to the PetSet created for MongoDB database.
KubeDB accept following fields to set in spec.podTemplate:
- metadata:
- annotations (pod’s annotation)
- labels (pod’s labels)
- controller:
- annotations (petset’s annotation)
- labels (petset’s labels)
- spec:
- containers
- volumes
- podPlacementPolicy
- initContainers
- imagePullSecrets
- nodeSelector
- affinity
- serviceAccountName
- schedulerName
- tolerations
- priorityClassName
- priority
- securityContext
- livenessProbe
- readinessProbe
- lifecycle
You can check out the full list here.
Uses of some field of spec.podTemplate
is described below,
NB. If spec.shardTopology
is set, then spec.podTemplate
needs to be empty. Instead use spec.shardTopology.<shard/configServer/mongos>.podTemplate
spec.podTemplate.spec.tolerations
The spec.podTemplate.spec.tolerations
is an optional field. This can be used to specify the pod’s tolerations.
spec.podTemplate.spec.volumes
The spec.podTemplate.spec.volumes
is an optional field. This can be used to provide the list of volumes that can be mounted by containers belonging to the pod.
spec.podTemplate.spec.podPlacementPolicy
spec.podTemplate.spec.podPlacementPolicy
is an optional field. This can be used to provide the reference of the podPlacementPolicy. This will be used by our Petset controller to place the db pods throughout the region, zone & nodes according to the policy. It utilizes kubernetes affinity & podTopologySpreadContraints feature to do so.
spec.podTemplate.spec.containers
The spec.podTemplate.spec.containers
can be used to provide the list containers and their configurations for to the database pod. some of the fields are described below,
spec.podTemplate.spec.containers[].name
The spec.podTemplate.spec.containers[].name
field used to specify the name of the container specified as a DNS_LABEL. Each container in a pod must have a unique name (DNS_LABEL). Cannot be updated.
spec.podTemplate.spec.containers[].args
spec.podTemplate.spec.containers[].args
is an optional field. This can be used to provide additional arguments to database installation.
spec.podTemplate.spec.containers[].env
spec.podTemplate.spec.containers[].env
is an optional field that specifies the environment variables to pass to the MongoDB docker image. To know about supported environment variables, please visit here.
Note that, KubeDB does not allow MONGO_INITDB_ROOT_USERNAME
and MONGO_INITDB_ROOT_PASSWORD
environment variables to set in spec.podTemplate.spec.env
. If you want to use custom superuser and password, please use spec.authSecret
instead described earlier.
If you try to set MONGO_INITDB_ROOT_USERNAME
or MONGO_INITDB_ROOT_PASSWORD
environment variable in MongoDB crd, Kubedb operator will reject the request with following error,
Error from server (Forbidden): error when creating "./mongodb.yaml": admission webhook "mongodb.validators.kubedb.com" denied the request: environment variable MONGO_INITDB_ROOT_USERNAME is forbidden to use in MongoDB spec
Also, note that KubeDB does not allow updating the environment variables as updating them does not have any effect once the database is created. If you try to update environment variables, KubeDB operator will reject the request with following error,
Error from server (BadRequest): error when applying patch:
...
for: "./mongodb.yaml": admission webhook "mongodb.validators.kubedb.com" denied the request: precondition failed for:
...At least one of the following was changed:
apiVersion
kind
name
namespace
spec.ReplicaSet
spec.authSecret
spec.init
spec.storageType
spec.storage
spec.podTemplate.spec.nodeSelector
spec.podTemplate.spec.env
spec.podTemplate.spec.containers[].resources
spec.podTemplate.spec.containers[].resources
is an optional field. This can be used to request compute resources required by containers of the database pods. To learn more, visit here.
spec.podTemplate.spec.imagePullSecret
KubeDB
provides the flexibility of deploying MongoDB database from a private Docker registry. spec.podTemplate.spec.imagePullSecrets
is an optional field that points to secrets to be used for pulling docker image if you are using a private docker registry. To learn how to deploy MongoDB from a private registry, please visit here.
spec.podTemplate.spec.nodeSelector
spec.podTemplate.spec.nodeSelector
is an optional field that specifies a map of key-value pairs. For the pod to be eligible to run on a node, the node must have each of the indicated key-value pairs as labels (it can have additional labels as well). To learn more, see here .
spec.podTemplate.spec.serviceAccountName
serviceAccountName
is an optional field supported by KubeDB Operator (version 0.13.0 and higher) that can be used to specify a custom service account to fine tune role based access control.
If this field is left empty, the KubeDB operator will create a service account name matching MongoDB crd name. Role and RoleBinding that provide necessary access permissions will also be generated automatically for this service account.
If a service account name is given, but there’s no existing service account by that name, the KubeDB operator will create one, and Role and RoleBinding that provide necessary access permissions will also be generated for this service account.
If a service account name is given, and there’s an existing service account by that name, the KubeDB operator will use that existing service account. Since this service account is not managed by KubeDB, users are responsible for providing necessary access permissions manually. Follow the guide here to grant necessary permissions in this scenario.
spec.serviceTemplates
You can also provide template for the services created by KubeDB operator for MongoDB database through spec.serviceTemplates
. This will allow you to set the type and other properties of the services.
KubeDB allows following fields to set in spec.serviceTemplates
:
alias
represents the identifier of the service. It has the following possible value:primary
is used for the primary service identification.standby
is used for the secondary service identification.stats
is used for the exporter service identification.
- metadata:
- labels
- annotations
- spec:
- type
- ports
- clusterIP
- externalIPs
- loadBalancerIP
- loadBalancerSourceRanges
- externalTrafficPolicy
- healthCheckNodePort
- sessionAffinityConfig
See here to understand these fields in detail.
spec.deletionPolicy
deletionPolicy
gives flexibility whether to nullify
(reject) the delete operation of MongoDB
crd or which resources KubeDB should keep or delete when you delete MongoDB
crd. KubeDB provides following four termination policies:
- DoNotTerminate
- Halt
- Delete (
Default
) - WipeOut
When deletionPolicy
is DoNotTerminate
, KubeDB takes advantage of ValidationWebhook
feature in Kubernetes 1.9.0 or later clusters to implement DoNotTerminate
feature. If admission webhook is enabled, DoNotTerminate
prevents users from deleting the database as long as the spec.deletionPolicy
is set to DoNotTerminate
.
Following table show what KubeDB does when you delete MongoDB crd for different termination policies,
Behavior | DoNotTerminate | Halt | Delete | WipeOut |
---|---|---|---|---|
1. Block Delete operation | ✓ | ✗ | ✗ | ✗ |
2. Delete PetSet | ✗ | ✓ | ✓ | ✓ |
3. Delete Services | ✗ | ✓ | ✓ | ✓ |
4. Delete PVCs | ✗ | ✗ | ✓ | ✓ |
5. Delete Secrets | ✗ | ✗ | ✗ | ✓ |
6. Delete Snapshots | ✗ | ✗ | ✗ | ✓ |
7. Delete Snapshot data from bucket | ✗ | ✗ | ✗ | ✓ |
If you don’t specify spec.deletionPolicy
KubeDB uses Delete
termination policy by default.
spec.halted
Indicates that the database is halted and all offshoot Kubernetes resources except PVCs are deleted.
spec.arbiter
If spec.arbiter
is not null, there will be one arbiter pod on each of the replicaset structure, including shards. It has two fields.
spec.arbiter.podTemplate
defines the arbiter-pod’s template. See spec.podTemplate part for more details of this.spec.arbiter.configSecret
is an optional field that allows users to provide custom configurations for MongoDB arbiter. You just need to refer the configuration secret inspec.arbiter.configSecret.name
field.
Please note that, the secret key needs to be
mongod.conf
.
N.B. If spec.replicaset
& spec.shardTopology
both is empty, spec.arbiter
has to be empty too.
spec.allowedSchemas
It defines which consumers may refer to a database instance. We implemented double-optIn feature between database instance and schema-manager using this field.
spec.allowedSchemas.namespace.from
indicates how you want to filter the namespaces, from which a schema-manager will be able to communicate with this db instance. Possible values are : i)All
to allow all namespaces, ii)Same
to allow only if schema-manager & MongoDB is deployed in same namespace & iii)Selector
to select some namespaces through labels.spec.allowedSchemas.namespace.selector
. You need to set this field only ifspec.allowedSchemas.namespace.from
is set toselector
. Here you will give the labels of the namespaces to allow.spec.allowedSchemas.selctor
denotes the labels of the schema-manager instances, which you want to give allowance to use this database.
spec.coordinator
We use a dedicated container, named replication-mode-detector
, to continuously select primary pod and add label as primary. By specifying spec.coordinator.resources
& spec.coordinator.securityContext
, you can set the resources and securityContext of that mode-detector container.
spec.healthChecker
It defines the attributes for the health checker.
spec.healthChecker.periodSeconds
specifies how often to perform the health check.spec.healthChecker.timeoutSeconds
specifies the number of seconds after which the probe times out.spec.healthChecker.failureThreshold
specifies minimum consecutive failures for the healthChecker to be considered failed.spec.healthChecker.disableWriteCheck
specifies whether to disable the writeCheck or not.
Know details about KubeDB Health checking from this blog post.
Next Steps
- Learn how to use KubeDB to run a MongoDB database here.
- Want to hack on KubeDB? Check our contribution guidelines.