Github user jtstorck commented on a diff in the pull request:
https://github.com/apache/nifi/pull/3056#discussion_r223912939
--- Diff: nifi-docs/src/main/asciidoc/administration-guide.adoc ---
@@ -2393,19 +2395,53 @@ When the DFM makes changes to the dataflow, the
node that receives the request t
nodes and waits for each node to respond, indicating that it has made the
change on its local flow.
-*Dealing with Disconnected Nodes* +
+=== Managing Nodes
+
+==== Disconnect Nodes
+
+A DFM may manually disconnect a node from the cluster. A node may also
become disconnected for other reasons, such as due to a lack of heartbeat. The
Cluster Coordinator will show a bulletin on the User Interface when a node is
disconnected. The DFM will not be able to make any changes to the dataflow
until the issue of the disconnected node is resolved. The DFM or the
Administrator will need to troubleshoot the issue with the node and resolve it
before any new changes can be made to the dataflow. However, it is worth noting
that just because a node is disconnected does not mean that it is not working.
This may happen for a few reasons, for example when the node is unable to
communicate with the Cluster Coordinator due to network problems.
+
+To manually disconnect a node, select the "Disconnect" icon
(image:iconDisconnect.png["Disconnect Icon"]) from the node's row.
+
+image::disconnected-node-cluster-mgt.png["Disconnected Node in Cluster
Management UI"]
+
+A disconnected node can be connected (image:iconConnect.png["Connect
Icon"]), offloaded (image:iconOffload.png["Offload Icon"]) or deleted
(image:iconDelete.png["Delete Icon"]).
+
+==== Offload Nodes
+
+Flowfiles that remain on a disconnected node can be rebalanced to other
active nodes in the cluster via offloading. In the Cluster Management dialog,
select the "Offload" icon (image:iconOffload.png["Offload Icon"]) for a
Disconnected node. This will stop all processors, terminate all processors,
stop transmitting on all remote process groups and rebalance flowfiles to the
other connected nodes in the cluster.
+
+image::offloading-node-cluster-mgt.png["Offloading Node in Cluster
Management UI"]
+
+Nodes that remain in "Offloading" state due to errors encountered (out of
memory, no network connection, etc.) can be reconnected to the cluster by
restarting NiFi on the node. Offloaded nodes can be either reconnected to the
cluster (by selecting Connect or restarting NiFi on the node) or deleted from
the cluster.
+
+image::offloaded-node-cluster-mgt.png["Offloaded Node in Cluster
Management UI"]
+
+==== Delete Nodes
+
+There are cases where a DFM may wish to continue making changes to the
flow, even though a node is not connected to the cluster. In this case, the DFM
may elect to delete the node from the cluster entirely. In the Cluster
Management dialog, select the "Delete" icon (image:iconDelete.png["Delete
Icon"]) for a Disconnected or Offloaded node. Once deleted, the node cannot be
rejoined to the cluster until it has been restarted.
+
+==== Decommission Nodes
+
+The steps to decommission a node and remove it from a cluster are as
follows:
+
+1. Disconnect the node.
+2. Once disconnect completes, offload the node.
+3. Once offload completes, delete the node.
+4. Once the delete request has finished, stop/remove the NiFi service on
the host.
+
+==== NiFi Toolkit Node Commands
-A DFM may manually disconnect a node from the cluster. But if a node
becomes disconnected for any other reason (such as due to lack of heartbeat),
-the Cluster Coordinator will show a bulletin on the User Interface. The
DFM will not be able to make any changes to the dataflow until the issue
-of the disconnected node is resolved. The DFM or the Administrator will
need to troubleshoot the issue with the node and resolve it before any
-new changes may be made to the dataflow. However, it is worth noting that
just because a node is disconnected does not mean that it is not working;
-this may happen for a few reasons, including that the node is unable to
communicate with the Cluster Coordinator due to network problems.
+As an alternative to the UI, the following NiFi Toolkit CLI commands can
be used for retrieving a single node, retrieving a list of nodes, and
connecting/disconnecting/offloading/deleting nodes:
-There are cases where a DFM may wish to continue making changes to the
flow, even though a node is not connected to the cluster.
-In this case, they DFM may elect to remove the node from the cluster
entirely through the Cluster Management dialog. Once removed,
-the node cannot be rejoined to the cluster until it has been restarted.
+* `nifi get-node`
--- End diff --
Should these commands be more verbose? Adding examples including
parameters for using the TLS Toolkit CLI commands securely would be beneficial.
Also, talking about the response types would be useful, since the simple
response type is more of a human readable summary, and the json response is the
complete entity that's returned from the API endpoint.
---
