@Techie123  When you say "Cooperates Linux Machine", are you referring to http://www.colinux.org/ installation? If so, this does not sound like an ideal place to try and run a NiFi instance or NiFi cluster as it appears to isolate that linux to a single core on the host hardware.  NiFi can be a resource intensive application, especially when setup as a cluster. When NiFi is started, you can tail the nifi-app.log to observe the complete startup process. NiFi has completed its startup once you see the following lines:   2022-06-15 13:52:52,727 INFO org.apache.nifi.web.server.JettyServer: NiFi has started. The UI is available at the following URLs: 2022-06-15 13:52:52,727 INFO org.apache.nifi.web.server.JettyServer: https://nifi-node1:8443/nifi 2022-06-15 13:52:52,730 INFO org.apache.nifi.BootstrapListener: Successfully initiated communication with Bootstrap   At this time the NiFi URL should be reachable.  If not, I would be making sure a firewall or some issue with your "Cooperates Linux Machine" setup is not blocking access to the port on which the NiFi is bound. The latter error you shared:   o.a.nifi.controller.StandardFlowService Failed to connect to cluster due to: org.apache.nifi.cluster.protocol.ProtocolException: Failed marshalling 'CONNECTION_REQUEST' protocol message due to: javax.net.ssl.SSLHandshakeException: PKIX path validation failed: java.security.cert.CertPathValidatorException: Path does not chain with any of the trust anchors   implies that your NiFi cluster has been setup to start secured over HTTPS. Secured NiFi nodes must have a configured keystore and truststore.  The above error is telling you that node's truststore does not contain the TrustedCertEntry(s) needed to trust the client certificate presented by another node (in this case the elected cluster coordinator node). The NiFi configured keystore must meet these requirements: 1. Contain only ONE PrivateKeyEntry. (this private key is typically unique per node) 2. That Private key must support both ClientAuth and ServerAuth EKUs 3. That PrivateKey must contain a SAN entry for the NiFI host on which it is being used.  That SAN must mach the hostname of the host. The NiFi configured truststore must contain the complete trust chain for the nodes private keys. You can use the keytool command to inspect the contents of either the keystore or truststore and verify above requirements are satisfied,   keytool -v -list -keystore <keystore or truststore>   A certificate (private "PrivateKeyEntry" or public "TrustedCertEntry") will have an owner an issuer.  The issuer is the authority for that key.  A self-signed certificate will have the same owner and issuer. The truststore needs to have a TrustedCertEntry for each public certificate in the trusts chain. For example: Assume you have a PrivateKey in your keystore with:   owner: cn=nifi-node1, ou=nifi Issuer: cn=intermediate-ca, ou=trust   Your Truststore would then need to have a TrustedCertEntry for the public key for:   owner: cn=intermediate-ca, ou=trust issuer: cn=root-ca, ou=trust   and:   owner: cn=root-ca, ou=trust issuer: cn=root-ca, ou=trust   You know you have the complete trust chain once you reach the public cert where owner and issuer have the same value. If you found this response assisted with your query, please take a moment to login and click on "Accept as Solution" below this post. Thank you, Matt ... View more

@Vapper  Maybe I am not 100% clear on your question here.. When you say new "flow file" I assume you are talking about the flow.xml.gz file? In NiFi, a "FlowFile" is what you see being queued on connections between processor components and consists of FlowFile content and FlowFile Metadata/Attributes. In a NiFi cluster, all nodes must be running the exact same flow.xml.gz.  If the dataflows loaded from the flow.xml.gz do not match the node will not be allowed to join the cluster.  In the latest releases of NiFi, Nodes joining a cluster will inherit the cluster dataflow if the local dataflow does not match. Once a cluster is established, a cluster dataflow is elected. That becomes the clusters dataflow. Joining a node to that established cluster will require that joining nodes is using same flow.xm.gz as existing cluster and if not inherit the cluster elected dataflow over the existing flow on the joining node. NiFi will not assume that a joining nodes flow.xml.gz is "newer" or "desired" over the elected cluster dataflow and replace the elected cluster dataflow with that new dataflow. If you found this response assisted with your query, please take a moment to login and click on "Accept as Solution" below this post. Thank you, Matt ... View more