Windows: a node upgraded from 3.11.15 to 4.1.2 stops immediately

[AlvariaIC]

Community Support Policy

• I have read RabbitMQ's Community Support Policy
• I run RabbitMQ 4.x, the only series currently covered by community support
• I promise to provide all relevant information (versions, logs from all nodes, rabbitmq-diagnostics output, detailed reproduction steps)

RabbitMQ version used

4.1.2

Erlang version used

27.3.x

Operating system (distribution) used

Windows Server 2019

How is RabbitMQ deployed?

Windows installer

rabbitmq-diagnostics status output

See https://www.rabbitmq.com/docs/cli to learn how to use rabbitmq-diagnostics

# PASTE OUTPUT HERE, BETWEEN BACKTICKS

Logs from node 1 (with sensitive values edited out)

See https://www.rabbitmq.com/docs/logging to learn how to collect logs

# PASTE LOG HERE, BETWEEN BACKTICKS

Logs from node 2 (if applicable, with sensitive values edited out)

See https://www.rabbitmq.com/docs/logging to learn how to collect logs

# PASTE LOG HERE, BETWEEN BACKTICKS

Logs from node 3 (if applicable, with sensitive values edited out)

See https://www.rabbitmq.com/docs/logging to learn how to collect logs

# PASTE LOG HERE, BETWEEN BACKTICKS

rabbitmq.conf

See https://www.rabbitmq.com/docs/configure#config-location to learn how to find rabbitmq.conf file location

# PASTE rabbitmq.conf HERE, BETWEEN BACKTICKS

Steps to deploy RabbitMQ cluster

This is a single server install. Installed OTP and RabbitMQ with the defaults. Since the service is crashing immediately nothing else was done to configure or test.

Steps to reproduce the behavior in question

uninstalled and tried 4.1.3 version, same behavior. rebooted etc. EV has errors for ERL and RabbitMQ

advanced.config

See https://www.rabbitmq.com/docs/configure#config-location to learn how to find advanced.config file location

# PASTE advanced.config HERE, BETWEEN BACKTICKS

Application code

# PASTE CODE HERE, BETWEEN BACKTICKS

Kubernetes deployment file

# Relevant parts of K8S deployment that demonstrate how RabbitMQ is deployed
# PASTE YAML HERE, BETWEEN BACKTICKS

What problem are you trying to solve?

RabbitMQ service stops immediately. This server was originally running 3.11.15 and 25.3.20 with no issues and those can be reinstalled and startup with no issues.
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[michaelklishin]

I do not see any evidence of a 4.1.2 node startup in the log. All startup banners are from 3.11.15.

2025-08-12 09:40:24.869000-07:00 [info] <0.95.0> RabbitMQ is asked to stop...

means that the node was stopped using rabbitmqctl.bat shutdown or a similar command.

@AlvariaIC most likely you are

1. Trying to go straight from 3.11 to 4.1 with an existing node data directory. That won't work because 4.1 nodes will require a feature flag that 3.11 cannot possibly have enabled (that flag did not exist back in the 3.11 days)
2. You end up with two Erlang versions, and 4.1 cannot possibly start on Erlang 25 because it was compiled on Erlang 26.2

If this is a development environment, removing RabbitMQ, Erlang, the data directory, then installing a compatible version of Erlang (27.3.x) and RabbitMQ 4.1.3 will help because the node won't have any existing state and will start as a brand new 4.1 node, without performing any upgrade time migrations that involve verification of feature flags and such.

[AlvariaIC]

That's interesting that it shows 3.11.15. I used the add/remove programs in windows to remove the two previous installs as I know how much fun it is to go from version to version. Is there any known issues with removal of the old version lingering causing problems with the new install? I can uninstall again and make sure all directory structures and registry entries are completely gone. This is one of the few customers I've had where we are repurposing existing servers, typically they provide new freshly built VM's.

[michaelklishin]

I have explained the key known "issue". If you can afford to wipe the data directory, then just do that.

Note that you can trivially back up all virtual hosts, users, topology and everything else besides messages, and then import the definitions file into the 4.1.3 cluster.

[AlvariaIC]

Appreciate the help. I'll work with the customer in the morning to see how it ends up. Honestly this product doesn't use hardly any of the features or clusters of RabbitMQ so there's never anything to worry about backing up and the only configuration the install person needs to do it just create a new user the application handles everything else automatically. It's been such a simple setup for so many years we don't even have anybody internally that knows anything about how its working and thus directly me to the community for support.