EBS volume gets unmounted on its own after a while-CodePudding

I recently created a EC2 instance and a 30GB EBS (gp3) volume. The logic to attach and mount the volume is in the EC2 instance's user data script (see below). The issue I am experiencing is that after several days the mounted EBS volume would be unmounted on its own. The EBS volume would be still attached to the EC2 instance, though.

this is my user-data script (simplified):

#!/bin/bash -xe
exec > >(tee /var/log/user-data.log|logger -t user-data -s 2>/dev/console) 2>&1

MONGO_DATA_DIR="/data"
EBS_DEVICE_NAME="nvme1n1"
VOLUME="/dev/$EBS_DEVICE_NAME"

sudo yum install -y mongodb-org

# attach EBS volume
EC2_INSTANCE_ID="$(wget -q -O - http://169.254.169.254/latest/meta-data/instance-id)"
aws ec2 attach-volume --volume-id ${volumeId} --instance-id $EC2_INSTANCE_ID --device /dev/sdh

# Create File System on the eEBS bs volume if needed
FileSystemType="$(lsblk -f | grep $EBS_DEVICE_NAME | awk '{print $2}')"

sudo mkfs -t xfs /dev/$EBS_DEVICE_NAME

# create mount point & mount volume disk if needed
if [ ! -d "$MONGO_DATA_DIR" ]; then
    echo "$MONGO_DATA_DIR does not exist."
    sudo mkdir -p $MONGO_DATA_DIR
    
    sudo mount /dev/$EBS_DEVICE_NAME $MONGO_DATA_DIR
    # change permissions to the data dir so it is owned by the mongod user
    sudo chown -R mongod $MONGO_DATA_DIR
fi

sudo systemctl start mongod
sudo systemctl enable mongod

As the mounted EBS data - /data is storing our Mongodb database the MongoDB service stops working.

What could be causing this automatic unmount behaviour and what would be the best way to resolve the issue?

Update

After adding the below changes to /etc/fstab the issue was fixed:

if [ ! -d "$MONGO_DATA_DIR" ]; then
...
     # make EBS mount permanent
     EBS_DEVICE_ID="$(sudo blkid -o value -s UUID /dev/$EBS_DEVICE_NAME)"
     sudo su -c "echo 'UUID=$EBS_DEVICE_ID  /data  xfs  defaults,nofail  0  2' >> /etc/fstab"
fi

CodePudding user response：

It sounds like your server is probably rebooting for some reason, and since you haven't modified /etc/fstab the volume won't be remounted automatically on boot.