EasyUC
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Aurora

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4.8.7

Installation, updates & backup

Adding, naming and removing nodes

Add further appliances to the cluster as nodes, assign display names and remove nodes.

EasyUC · Version 4.8.7

In EasyUC: Manager → Übersicht → Knoten card

What it is for

An EasyUC installation runs on one node or on several. You add further nodes in the Manager: you enter the IP address of a prepared EasyUC appliance, the Manager connects to it over SSH, sets the host name and installs K3s from the files of the appliance. The new node joins the cluster as a full server and also takes on services.

With several nodes the storage (Longhorn) keeps copies of the volumes on several nodes. Three nodes are needed for the cluster control plane to survive a failure, see the chapter "High availability with three nodes".

Prerequisites

  • A login to the Manager.
  • An imported EasyUC appliance that has not been initialised yet, with its IP address set. Initialize K3s is not run on the new node.
  • The new node is reachable from the first node over SSH on TCP 15222. All nodes are in the same network segment; there is no filtering between the nodes.
  • The time of all nodes is synchronised with the same internal time source.
  • For updates and a possible move of the Manager, the images of the installed levels must be on all nodes. The EasyUC-Update page distributes application images by itself.

Step by step: add a node

  1. Open the Übersicht page in the Manager.
  2. On the Knoten card, select Knoten hinzufügen.
  3. In the dialog Neuen Knoten hinzufügen, enter the IP-Adresse.
  4. If required, enter a Knotenname (optional), for example ubc-knoten-2.
  5. Select Anlegen.
  6. Follow the log in the dialog: SSH test, preparation of the cluster configuration, installation of K3s, joining the cluster.
  7. Wait until the node appears on the Knoten card with the state "Bereit".

Step by step: assign a display name

  1. On the node card, select the pencil icon next to the name.
  2. Enter the Anzeigename, for example "Zentrale Hamburg".
  3. Select Speichern. The technical name stays unchanged and is shown below.

Step by step: remove a node

  1. On the Speicher card, check that it reports "alle gesund", meaning that copies of the volumes exist on other nodes.
  2. On the node card, select the bin icon Knoten entfernen.
  3. Confirm the dialog Delete node with Delete.
  4. Follow the log: the Manager blocks the node for new services, moves the running services, removes the node from the cluster and uninstalls K3s on the node.

Fields and options

Field / actionMeaning and use
IP-AdresseMandatory. Address of the prepared appliance.
Knotenname (optional)Lower-case letters, digits and hyphens, at most 63 characters; it must start and end with a letter or digit. Without an entry the Manager assigns a name itself. Cannot be changed later.
AnzeigenameFreely chosen label for the interface. Leaving it empty removes the display name.
Zustand"Bereit" or "Nicht bereit", below it Speicher, Platte and Prozesse, each with "in Ordnung" or "Druck".
CPU / Speicher / PlatteLoad of the node with history.
Speicher cardLonghorn volumes with usage and redundancy per volume. States: "alle gesund", "eingeschränkt" (copies missing), "abgetrennt", "ausgefallen".
Docker Images cardContainer images in the cluster and on how many nodes they are present. Load Images loads an image archive for installations without internet access.

Check the result and troubleshoot

  • The node is shown on the Knoten card with "Bereit", version and IP address.
  • "Cannot establish SSH connection to …": the appliance is not reachable at that address over SSH on TCP 15222. Check network and firewall.
  • "A master node with IP … already exists in the cluster.": the address already belongs to a node.
  • "Ein Knoten mit dem Namen … existiert bereits im Cluster.": choose another name.
  • "Erlaubt sind Kleinbuchstaben, Ziffern und Bindestriche; Anfang und Ende müssen Buchstabe oder Ziffer sein": correct the node name.
  • "Cannot remove the last master node from the cluster": the last node cannot be removed.
  • Changing the IP address through the console menu is only possible for installations with one node.

Related chapters