Alertmanager v0.26.0

[Josue Abreu]

Hello Prometheans,

We're pleased to announce the release of Alertmanager v0.26. It is available from the GitHub release page [1] or from your favorite container registry (Docker Hub or Quay).

This release includes a hefty number of improvements and an important security fix - it's highly recommended you update.

Changelog:

• [CHANGE] Telegram Integration: `api_url` is now optional. #2981
• [CHANGE] Telegram Integration: `ParseMode` default is now `HTML` instead of `MarkdownV2`. #2981
• [CHANGE] Webhook Integration: `url` is now marked as a secret. It will no longer show up in the logs as clear-text. #3228
• [CHANGE] Metrics: New label `reason` for `alertmanager_notifications_failed_total` metric to indicate the type of error of the alert delivery. #3094 #3307
• [FEATURE] Clustering: New flag `--cluster.label`, to help to block any traffic that is not meant for the cluster. #3354
• [FEATURE] Integrations: Add Microsoft Teams as a supported integration. #3324
• [ENHANCEMENT] Telegram Integration: Support `bot_token_file` for loading this secret from a file. #3226
• [ENHANCEMENT] Webhook Integration: Support `url_file` for loading this secret from a file. #3223
• [ENHANCEMENT] Webhook Integration: Leading and trailing white space is now removed for the contents of `url_file`. #3363
• [ENHANCEMENT] Pushover Integration: Support options `device` and `sound` (sound was previously supported but undocumented). #3318
• [ENHANCEMENT] Pushover Integration: Support `user_key_file` and `token_file` for loading this secret from a file. #3200
• [ENHANCEMENT] Slack Integration: Support errors wrapped in successful (HTTP status code 200) responses. #3121
• [ENHANCEMENT] API: Add `CORS` and `Cache-Control` HTTP headers to all version 2 API routes. #3195
• [ENHANCEMENT] UI: Receiver name is now visible as part of the alerts page. #3289
• [ENHANCEMENT] Templating: Better default text when using `{{ .Annotations }}` and `{{ .Labels }}`. #3256
• [ENHANCEMENT] Templating: Introduced a new function `trimSpace` which removes leading and trailing white spaces. #3223
• [ENHANCEMENT] CLI: `amtool silence query` now supports the `--id` flag to query an individual silence. #3241
• [ENHANCEMENT] Metrics: Introduced `alertmanager_nflog_maintenance_total` and `alertmanager_nflog_maintenance_errors_total` to monitor maintenance of the notification log. #3286
• [ENHANCEMENT] Metrics: Introduced `alertmanager_silences_maintenance_total` and `alertmanager_silences_maintenance_errors_total` to monitor maintenance of silences. #3285
• [ENHANCEMENT] Logging: Log GroupKey and alerts on alert delivery when using debug mode. #3438
• [BUGFIX] Configuration: Empty list of `receivers` and `inhibit_rules` would cause the alertmanager to crash. #3209
• [BUGFIX] Templating: Fixed a race condition when using the `title` function. It is now race-safe. #3278
• [BUGFIX] API: Fixed duplicate receiver names in the `api/v2/receivers` API endpoint. #3338
• [BUGFIX] API: Attempting to delete a silence now returns the correct status code, `404` instead of `500`. #3352
• [BUGFIX] Clustering: Fixes a panic when `tls_client_config` is empty. #3443
• [BUGFIX] Fix stored XSS via the /api/v1/alerts endpoint in the Alertmanager UI.
  

[1] https://github.com/prometheus/alertmanager/releases/tag/v0.26.0