Teleport service logs get overwritten on restart

[anurag-work]

Description

Log file /var/lib/teleport/teleport.log gets overwritten when service is restarted
What you expected to happen:
The file should be appended to

Reproduction Steps

As minimally and precisely as possible, describe step-by-step how to reproduce the problem.

1. Setup teleport as a service

[Unit]
Description=Teleport SSH Service
After=network.target

[Service]
Type=simple
User=teleport
Group=teleport
Restart=on-failure
EnvironmentFile=-/etc/default/teleport
ExecStart=/usr/local/bin/teleport start --pid-file=/var/lib/teleport/teleport.pid --diag-addr=0.0.0.0:3030 --config=/var/lib/teleport/teleport.yaml
ExecReload=/bin/kill -HUP $MAINPID
PIDFile=/var/lib/teleport/teleport.pid
LimitNOFILE=8192

[Install]
WantedBy=multi-user.target

teleport.yaml

teleport:
  log:
    output: /var/lib/teleport/teleport.log
    severity: DEBUG

2. Restart teleport service

Server Details

• Teleport version (run teleport version): 6.0.1
• Server OS (e.g. from /etc/os-release): ubuntu 20.04/centos 7.9
• Where are you running Teleport? (e.g. AWS, GCP, Dedicated Hardware): on prem
• Additional details:

This makes debugging issues nearly impossible

[zmb3]

This was fixed with #43359