There could be network connectivity issues between Cassandra pods in different data centers.
Apigee hybrid
Common diagnosis steps
Fetch the status of the data replication:
kubectl -n apigee get apigeeds \ -o jsonpath="{.items[].status.cassandraDataReplication}{'\n'}"
If you see an error with a message similar to the one specified in
Error message, then it indicates that you are
observing this issue.
Cause: Incorrect source region
If you specify a source region (datacenter) in your data replication YAML file that
is different from the actual source datacenter, then the data replication will
fail. Perform the steps in Diagnosis to analyze this scenario and
perform the steps in Resolution to correct it.
Diagnosis
List all the Cassandra pods in the source region:
kubectl -n apigee get pods -l app=apigee-cassandra
Get the actual datacenter value from any one of the Cassandra pods returned
in step 1:
Get the value used for source.region in the Cassandra data replication
custom resource (YAML) file you created in
Multi-region deployment. If you are using the example file name found in the
Multi-region deployment documentation, then the file should be named
datareplication.yaml.
Datacenter: dc-1================
Status=Up/Down
|/ State=Normal/Leaving/Joining/Moving
-- Address Load Tokens Owns (effective) Host ID Rack
UN 10.104.13.2 491.84 KiB 256 100.0% 7254711c-fe0a-4b34-b50f-861109f97936 ra-1
UN 10.104.11.3 527.36 KiB 256 100.0% 5ec389f0-fd67-4de6-9f21-172d5899ff78 ra-1
UN 10.104.12.7 838.46 KiB 256 100.0% 7a88be82-1f81-4117-86e3-2cda434c0878 ra-1
Note that the source.region (us-west1) from the
datareplication.yaml file does not match the actual datacenter value
(dc-1) from the nodetool status output. Follow the steps in
Resolution to correct the configuration.
Resolution
To correct the data replication, you'll need to delete the data replication job and create it
with the correct datacenter name. Perform the following steps:
Delete the current data replication process. If using the example file name found in the
Multi-region deployment documentation, then the file should be named
datareplication.yaml.
kubectl delete -f datareplication.yaml
Update the region name in the YAML file to the correct datacenter value, e.g.
dc-1:
The data replication error may also be the result of connectivity issues between Cassandra
nodes.
Diagnosis
Perform the following steps to analyze this scenario:
List all the Cassandra pods:
# list cassandra pods
kubectl -n=apigee get pods -l app=apigee-cassandra
Execute the following commands to telnet to the first Cassandra pod in the
second data center (dc-2) from the first Cassandra pod in the first data center
(dc-1) using port 7001:
k debug -it apigee-cassandra-default-0 -n apigee --image=nginx -- sh curl -v telnet://DC_2_APIGEE_CASSANDRA_DEFAULT_0_POD_IP:7001
If telnet was successful, an output similar to following is displayed:
* Rebuilt URL to: telnet://10.0.4.10:7001/
* Trying 10.0.4.10...
* TCP_NODELAY set
* Connected to 10.0.4.10 (10.0.4.10) port 7001 (#0)
Otherwise, an error similar to following is displayed:
* Rebuilt URL to: telnet://10.0.4.10:7001/
* Trying 10.0.4.10...
* TCP_NODELAY set
* connect to 10.0.4.10 port 7001 failed: Connection refused
* Failed to connect to 10.0.4.10 port 7001: Connection refused
* Closing connection 0
curl: (7) Failed to connect to 10.0.4.10 port 7001: Connection refused
The connectivity failure from the Cassandra pod in one data center to the Cassandra pod in
another data center indicates that there must be a firewall restriction or some sort of
network connectivity issue.
Resolution
If this Apigee hybrid deployment is on GKE, check to see if any firewall rules are set that
block the traffic from one data center to another and analyze the network connectivity
problem by referring to
VPC firewall rules overview.
If this Apigee hybrid deployment is on GKE-on-prem, work with the relevant networking
team and analyze the network connectivity problem.
If the problem persists even after following the above instructions, gather the following
diagnostic information and then contact Google Cloud Customer Care:
The Google Cloud Project ID.
The Apigee hybrid organization.
The overrides.yaml files from both source and new regions,
masking any sensitive information.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-28 UTC."],[[["\u003cp\u003eThis documentation addresses data replication failures in Apigee hybrid multi-region deployments, specifically when the \u003ccode\u003eCassandraDataReplication\u003c/code\u003e status indicates an error.\u003c/p\u003e\n"],["\u003cp\u003eA common cause of replication failure is an incorrect source region specified in the Cassandra data replication YAML file, which can be diagnosed by comparing the \u003ccode\u003esource.region\u003c/code\u003e with the \u003ccode\u003edatacenter\u003c/code\u003e value from the \u003ccode\u003enodetool status\u003c/code\u003e command.\u003c/p\u003e\n"],["\u003cp\u003eAnother potential cause of replication failure is network connectivity issues between Cassandra pods in different data centers, which can be diagnosed using \u003ccode\u003ecurl\u003c/code\u003e and \u003ccode\u003etelnet\u003c/code\u003e to check for connection refusals.\u003c/p\u003e\n"],["\u003cp\u003eResolution for an incorrect source region involves deleting the existing data replication job, updating the YAML file with the correct \u003ccode\u003edatacenter\u003c/code\u003e value, and reapplying the configuration.\u003c/p\u003e\n"],["\u003cp\u003eResolution for network issues involves checking firewall rules in GKE or working with the networking team in GKE-on-prem, ensuring connectivity between Cassandra nodes across regions.\u003c/p\u003e\n"]]],[],null,["# Cassandra data replication failure\n\n*You're viewing **Apigee** and **Apigee hybrid** documentation.\nView [Apigee Edge](https://docs.apigee.com/api-platform/troubleshoot/404-support-d) documentation.*\n| **Note:** This document is applicable for Apigee hybrid users only.\n\nSymptom\n-------\n\n\nWhen replicating data during a multi-region expansion, the `CassandraDataReplication`\nstatus may show an error state and data replication may fail.\n\nError message\n-------------\n\nWhen you use\n[kubectl](https://kubernetes.io/docs/reference/generated/kubectl/kubectl-commands) to view the rebuild status: \n\n```\n kubectl -n apigee get apigeeds \\\n -o jsonpath=\"{.items[].status.cassandraDataReplication}{'\\n'}\"\n```\n\nYou see that one or more Cassandra pods show an error state and a message stating the rebuild\nhas failed. For example: \n\n```scdoc\n{\n \"rebuildDetails\": {\n \"apigee-cassandra-default-0\": {\n \"message\": \"failed to rebuild from us-west1: java.lang.IllegalStateException : Unable to find sufficient sources for streaming range (-8567285182390470134,-8567154549835592965] in keyspace system_distributed\",\n \"state\": \"error\",\n \"updated\": 1641581899\n },\n …\n }\n}\n```\n\nPossible causes\n---------------\n\nCommon diagnosis steps\n----------------------\n\n1. Fetch the status of the data replication: \n\n ```\n kubectl -n apigee get apigeeds \\\n -o jsonpath=\"{.items[].status.cassandraDataReplication}{'\\n'}\"\n ```\n2. If you see an error with a message similar to the one specified in [Error message](#error-message), then it indicates that you are observing this issue.\n\nCause: Incorrect source region\n------------------------------\n\n\nIf you specify a source region (`datacenter`) in your data replication YAML file that\nis different from the actual source `datacenter`, then the data replication will\nfail. Perform the steps in [Diagnosis](#diagnosis) to analyze this scenario and\nperform the steps in [Resolution](#resolution) to correct it.\n\n### Diagnosis\n\n1. List all the Cassandra pods in the source region: \n\n ```\n kubectl -n apigee get pods -l app=apigee-cassandra\n ```\n2. Get the actual `datacenter` value from any one of the Cassandra pods returned in [step 1](#step-1): \n\n ```\n kubectl -n apigee exec -it apigee-cassandra-default-0 -- \\\n nodetool -u JMX_user -pw JMX_password status\n ```\n3. Get the value used for `source.region` in the Cassandra data replication custom resource (YAML) file you created in [Multi-region deployment](/apigee/docs/hybrid/latest/multi-region#configure-apigee-hybrid-for-multi-region). If you are using the example file name found in the Multi-region deployment documentation, then the file should be named `datareplication.yaml`. \n\n ```\n cat datareplication.yaml\n ```\n\n Example results: \n\n ```actionscript-3\n apiVersion: apigee.cloud.google.com/v1alpha1\n kind: CassandraDataReplication\n metadata:\n name: region-expansion\n namespace: apigee\n spec:\n organizationRef: apigee-hybrid-example-org\n force: false\n source:\n region: \"us-west1\"\n ```\n4. Check the result of the `nodetool status` output and verify whether or\n not the `datacenter` value matches the `source.region` value:\n\n ```\n kubectl -n apigee exec -it apigee-cassandra-default-0 -- \\\n nodetool -u jmxuser -pw iloveapis123 status\n ```\n\n Example results: \n\n ```restructuredtext\n Datacenter: dc-1\n ================\n Status=Up/Down\n |/ State=Normal/Leaving/Joining/Moving\n -- Address Load Tokens Owns (effective) Host ID Rack\n UN 10.104.13.2 491.84 KiB 256 100.0% 7254711c-fe0a-4b34-b50f-861109f97936 ra-1\n UN 10.104.11.3 527.36 KiB 256 100.0% 5ec389f0-fd67-4de6-9f21-172d5899ff78 ra-1\n UN 10.104.12.7 838.46 KiB 256 100.0% 7a88be82-1f81-4117-86e3-2cda434c0878 ra-1\n ```\n5. Note that the `source.region` (`us-west1`) from the `datareplication.yaml` file does not match the actual `datacenter` value (`dc-1`) from the `nodetool` status output. Follow the steps in [Resolution](#resolution) to correct the configuration.\n\n### Resolution\n\n\nTo correct the data replication, you'll need to delete the data replication job and create it\nwith the correct `datacenter` name. Perform the following steps:\n\n1. Delete the current data replication process. If using the example file name found in the [Multi-region deployment](/apigee/docs/hybrid/latest/multi-region#configure-apigee-hybrid-for-multi-region) documentation, then the file should be named `datareplication.yaml`. \n\n ```\n kubectl delete -f datareplication.yaml\n ```\n2. Update the region name in the YAML file to the correct `datacenter` value, e.g. `dc-1`: \n\n ```actionscript-3\n apiVersion: apigee.cloud.google.com/v1alpha1\n kind: CassandraDataReplication\n metadata:\n name: region-expansion\n namespace: apigee\n spec:\n organizationRef: apigee-hybrid-example-org\n force: false\n source:\n region: \"dc-1\"\n ```\n3. Apply the updated data replication: \n\n ```\n kubectl apply -f datareplication.yaml\n ```\n4. Check the rebuild status using the following command and verify that you no longer see the error state previously reported: \n\n ```\n kubectl -n apigee get apigeeds \\\n -o jsonpath=\"{.items[].status.cassandraDataReplication}{'\\n'}\"\n ```\n5. If the problem still persists, proceed to [Cause: Network connectivity issues.](#network-connectivity-issues)\n\nCause: Network connectivity issues\n----------------------------------\n\nThe data replication error may also be the result of connectivity issues between Cassandra\nnodes.\n| **Note:** Connectivity must be checked between all Cassandra nodes in all regions.\n\n### Diagnosis\n\n\nPerform the following steps to analyze this scenario:\n\n1. List all the Cassandra pods: \n\n ```text\n # list cassandra pods\n kubectl -n=apigee get pods -l app=apigee-cassandra\n ```\n2. Execute the following commands to telnet to the first Cassandra pod in the second data center (`dc-2`) from the first Cassandra pod in the first data center (`dc-1`) using port `7001`: \n\n ```scdoc\n k debug -it apigee-cassandra-default-0 -n apigee --image=nginx -- sh curl -v telnet://DC_2_APIGEE_CASSANDRA_DEFAULT_0_POD_IP:7001\n ```\n3. If telnet was successful, an output similar to following is displayed: \n\n ```scdoc\n * Rebuilt URL to: telnet://10.0.4.10:7001/\n * Trying 10.0.4.10...\n * TCP_NODELAY set\n * Connected to 10.0.4.10 (10.0.4.10) port 7001 (#0)\n ```\n4. Otherwise, an error similar to following is displayed: \n\n ```scdoc\n * Rebuilt URL to: telnet://10.0.4.10:7001/\n * Trying 10.0.4.10...\n * TCP_NODELAY set\n * connect to 10.0.4.10 port 7001 failed: Connection refused\n * Failed to connect to 10.0.4.10 port 7001: Connection refused\n * Closing connection 0\n curl: (7) Failed to connect to 10.0.4.10 port 7001: Connection refused\n ```\n\n\n The connectivity failure from the Cassandra pod in one data center to the Cassandra pod in\n another data center indicates that there must be a firewall restriction or some sort of\n network connectivity issue.\n\n### Resolution\n\n1. If this Apigee hybrid deployment is on GKE, check to see if any firewall rules are set that block the traffic from one data center to another and analyze the network connectivity problem by referring to [VPC firewall rules overview](https://cloud.google.com/vpc/docs/firewalls).\n2. If this Apigee hybrid deployment is on GKE-on-prem, work with the relevant networking team and analyze the network connectivity problem.\n\nIf the problem still persists, go to [Must gather diagnostic information](#must-gather).\n\nMust gather diagnostic information\n----------------------------------\n\n\nIf the problem persists even after following the above instructions, gather the following\ndiagnostic information and then contact [Google Cloud Customer Care](https://cloud.google.com/support-hub/):\n\n1. The Google Cloud Project ID.\n2. The Apigee hybrid organization.\n3. The `overrides.yaml` files from both source and new regions, masking any sensitive information.\n4. The `CassandraDataReplication` YAML file.\n5. Cassandra `nodetool status` output: \n\n ```\n kubectl -n apigee exec -it apigee-cassandra-default-0 -- \\\n nodetool -u JMX_user -pw JMX_password status\n ```\n6. Cassandra `nodetool describecluster` output: \n\n ```\n kubectl -n apigee exec -it apigee-cassandra-default-0 -- \\\n nodetool -u JMX_user -pw JMX_password describecluster\n ```"]]
