Question

MongoDB updated this morning to 7.0.1, now wont restart

Posted on September 7, 2023
MongoDB Database
Asked by tom

We have a pod running a MongoDB instance. It was automatically upgraded this morning to 7.0.1 and now wont restart citing;

initandlisten","msg":"Wrong mongod version","attr":{"error":"UPGRADE PROBLEM: Found an invalid featureCompatibilityVersion document (ERROR: Location4926900: Invalid featureCo │
│ mpatibilityVersion document in admin.system.version: { _id: \"featureCompatibilityVersion\", version: \"5.0\" }. See https://docs.mongodb.com/master/release-notes/6.0-compatibility/#feature-compatibility. :: caused by :: Invalid feature compatibility version value '5. │
│ 0'; expected '6.0' or '6.3' or '7.0'

Where would I update this Compatibility version? The pod isn’t running at this point.

Or can I fix the version of MongoDB on the pod to a prior version.

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Bobby Iliev

Site Moderator

• September 10, 2023

Accepted Answer

Hi there,

Based on the output that you’ve shared it seems that MongoDB was upgraded to a newer version without the featureCompatibilityVersion being upgraded in stages.

When upgrading MongoDB across multiple major versions, it’s recommended to upgrade one major version at a time and update the featureCompatibilityVersion in between.

Here’s what you can do to recover:

Always make sure to backup your data before performing any upgrade operations.

1. Downgrade MongoDB:

First, downgrade your MongoDB to the previous stable version you were using (e.g., 5.0).

As you mentioned that it is a MongoDB pod, I would assume that you are using Kubernetes, you can change the image version in your MongoDB deployment configuration.

For instance:

spec:
  containers:
  - name: mongodb
    image: mongo:5.0

After making the change, apply the updated configuration:

kubectl apply -f your-deployment-file.yaml

Once the pod is running with the downgraded version, verify that you can connect to your MongoDB instance.

2. Set the featureCompatibilityVersion:

Connect to your MongoDB instance and set the featureCompatibilityVersion:

mongo

db.adminCommand({ setFeatureCompatibilityVersion: "5.0" });

3. Upgrade Step-by-step:

Now, when you’re ready to upgrade:

Upgrade to MongoDB 6.0 and update featureCompatibilityVersion to “6.0”.
Then, if needed, upgrade to MongoDB 6.3 and update featureCompatibilityVersion to “6.3”.
Finally, upgrade to MongoDB 7.0 and set featureCompatibilityVersion to “7.0”.

Always make sure to backup your data before performing any upgrade operations.

Preventing Automatic Upgrades:

To prevent unexpected upgrades in the future, always pin your MongoDB version in your Kubernetes configurations (or whatever method you use to deploy). For instance, instead of using mongo:latest as your image, use mongo:5.0 or whatever specific version you intend to use.

Let me know how it goes!

Best,

Bobby