Timezone information is not included in mimir and mimirtool

[nasonfish]

Describe the bug

When using Location for muting rules in alertmanager using the docker images grafana/mimirtool and grafana/mimir, they are not aware of any timezones.

To Reproduce

Steps to reproduce the behavior:

1. Create an alertmanager configuration with a silencing rule using location: America/Denver
2. Run mimirtool alertmanager verify on your alertmanager configuration

mimirtool: error: unknown time zone America/Denver, try --help

If you get past this and apply to a running Mimir instance, you get this error:

mimirtool: error: POST request to https://mimir.<redacted>/api/v1/alerts failed: server returned HTTP status: 400 Bad Request, body: "error validating Alertmanager config: unknown time zone America/Denver\n", try --help

Expected behavior

This timezone should be recognized by default and an alerting rule should be able to be created.

Environment

• Infrastructure: Kubernetes
• Deployment tool: GitLab CI

Additional Context

Populating the /usr/share/zoneinfo directory seems to fix the problem, which can be done easily in alpine using apk add tzdata.