Documentation

    PLEASE NOTE: This document applies to an unreleased version of Rook. It is strongly recommended that you only use official releases of Rook, as unreleased versions are subject to changes and incompatibilities that will not be supported in the official releases.

    If you are using an official release version of Rook, you should refer to the documentation for your specific version.

    Documentation for other releases can be found by using the version selector in the bottom left of any doc page.

    EdgeFS iSCSI Target CRD

    Rook allows creation and customization of High Performance iSCSI Target compatible services through the custom resource definitions (CRDs). The following settings are available for customization of iSCSI Target services.

    Sample

    apiVersion: edgefs.rook.io/v1beta1
    kind: ISCSI
    metadata:
      name: iscsi01
      namespace: rook-edgefs
    spec:
      #chunkCacheSize: 1Gi
      placement:
      #  nodeAffinity:
      #    requiredDuringSchedulingIgnoredDuringExecution:
      #      nodeSelectorTerms:
      #      - matchExpressions:
      #        - key: role
      #          operator: In
      #          values:
      #          - iscsi-node
      #  tolerations:
      #  - key: iscsi-node
      #    operator: Exists
      #  podAffinity:
      #  podAntiAffinity:
      #resourceProfile: embedded
      resources:
      #  limits:
      #    cpu: "500m"
      #    memory: "1024Mi"
      #  requests:
      #    cpu: "500m"
      #    memory: "1024Mi"
      # A key/value list of annotations
      annotations:
      #  key: value
    

    Metadata

    • name: The name of the iSCSI target service to create, which must match existing EdgeFS service.
    • namespace: The namespace of the Rook cluster where the iSCSI Target service is created.
    • targetName: The name for iSCSI target name. Default is iqn.2018-11.edgefs.io.
    • targetParams: If specified, then some of iSCSI target protocol parameters can be overridden.
      • MaxRecvDataSegmentLength: Value in range value range 512..16777215. Default is 524288.
      • DefaultTime2Retain: Value in range 0..3600. Default is 60.
      • DefaultTime2Wait: Value in range 0..3600. Default is 30.
      • FirstBurstLength: Value in range 512..16777215. Default is 524288.
      • MaxBurstLength: Value in range 512..16777215. Default is 1048576.
      • MaxQueueCmd: Value in range 1..128. Default is 64.
    • chunkCacheSize: Limit amount of memory allocated for dynamic chunk cache. By default iSCSI pod uses up to 75% of available memory as chunk caching area. This option can influence this allocation strategy.
    • annotations: Key value pair list of annotations to add.
    • placement: The iSCSI pods can be given standard Kubernetes placement restrictions with nodeAffinity, tolerations, podAffinity, and podAntiAffinity similar to placement defined for daemons configured by the cluster CRD.
    • resourceProfile: iSCSI pod resource utilization profile (Memory and CPU). Can be embedded or performance (default). In case of performance an iSCSI pod trying to increase amount of internal I/O resources that results in higher performance at the cost of additional memory allocation and more CPU load. In embedded profile case, iSCSI pod gives preference to preserving memory over I/O and limiting chunk cache (see chunkCacheSize option). The performance profile is the default unless cluster wide embedded option is defined.
    • resources: Set resource requests/limits for the iSCSI pods, see Resource Requirements/Limits.

    Setting up EdgeFS namespace and tenant

    For more detailed instructions please refer to EdgeFS Wiki.

    Below is an exampmle procedure to get things initialized and configured.

    Before new local namespace (or local site) can be used, it has to be initialized with FlexHash and special purpose root object.

    FlexHash consists of dynamically discovered configuration and checkpoint of accepted distribution table. FlexHash is responsible for I/O direction and plays important role in dynamic load balancing logic. It defines so-called Negotiating Groups (typically across zoned 8-24 disks) and final table distribution across all the participating components, e.g. data nodes, service gateways and tools.

    Root object holds system information and table of namespaces registered to a local site. Root object is always local and never shared between the sites.

    To initialize system and prepare logical definitions, login to the toolbox as shown in this example:

    kubectl get po --all-namespaces | grep edgefs-mgr
    kubectl exec -it -n rook-edgefs rook-edgefs-mgr-6cb9598469-czr7p -- env COLUMNS=$COLUMNS LINES=$LINES TERM=linux toolbox
    

    Assumption at this point is that nodes are all configured and can be seen via the following command:

    efscli system status
    
    1. Initialize cluster

    Verify that HW (or better say emulated in this case) configuration look normal and accept it

    efscli system init
    

    At this point new dynamically discovered configuration checkpoint will be created at $NEDGE_HOME/var/run/flexhash-checkpoint.json This will also create system “root” object, holding Site’s Namespace. Namespace may consist of more then single region.

    1. Create new local namespace (or we also call it “Region” or “Segment”)
    efscli cluster create Hawaii
    
    1. Create logical tenants of cluster namespace “Hawaii”, also buckets if needed
    efscli tenant create Hawaii/Cola
    efscli bucket create Hawaii/Cola/bk1
    efscli tenant create Hawaii/Pepsi
    efscli bucket create Hawaii/Pepsi/bk1
    

    Now cluster is setup, services can be now created.

    1. Create iSCSI Target services objects for tenants
    efscli service create iscsi isc-cola
    efscli service serve isc-cola Hawaii/Cola/bk1/lun1 X-volsize=10G,ccow-chunkmap-chunk-size=16384
    efscli service serve isc-cola Hawaii/Cola/bk1/lun2 X-volsize=20G,ccow-chunkmap-chunk-size=131072
    efscli service create iscsi isc-pepsi
    efscli service serve isc-pepsi Hawaii/Pepsi/bk1/lun1 X-volsize=20G
    
    1. Create ISCSI CRDs
    apiVersion: edgefs.rook.io/v1beta1
    kind: ISCSI
    metadata:
      name: iscCola
      namespace: rook-edgefs
    
    apiVersion: edgefs.rook.io/v1beta1
    kind: ISCSI
    metadata:
      name: iscPepsi
      namespace: rook-edgefs
    

    At this point two iSCSI Target services should be available and listening on default port 3260.