Listing Unmuted Datadog Alerts

Datadogs UI for alerting monitors also shows muted ones without an option to filter, which leads to overhead / confusion when trying to track down what exactly is down.

So we added an alerts task to  kennel  that lists all unmuted alerts and since when they are alerting, it also shows alerts that have no-data warnings even though Datadog UI shows them as not alerting.

bundle exec rake kennel:alerts TAG=team:my-team
Downloading ... 5.36s
Foo certs will expire soon🔒
Ignored cluster:pod1,server: 39:22:00
Ignored cluster:pod12,server: 31:41:00
Ignored cluster:pod12,server: 31:41:00

Foobar Errors (Retry Limit Exceeded)🔒
Alert cluster:pod2 19:05:16

Ruby: Waiting for one of multiple threads to finish

We build a small project that watches multiple metrics until one of them finds something, I found ThreadsWait in the stdlib and it was easy to use it. Also added error re-raising so the threads do not die silently and cleanup.

require 'thwait'

def wait_for_first_block_to_complete(*blocks)
  threads = do |block| do
    rescue StandardError => e
  waiter =*threads)
  value = waiter.next_wait.value
  raise value if value.is_a?(StandardError)

  -> { sleep 5 }, -> { sleep 1 }, -> { sleep 2 }
) # will stop after 1 second


Reading journald kernel logs from inside a kubernetes pod

We wanted a watcher that alerts us when bad kernel things happen and were able to deploy that as a DaemonSet using Kubernetes 🙂

  • Use a Debian base image (for example ruby:2.5-stretch)
  • Run as root user or as user that can read systemd logs like systemd-journal
  • Mount /run/log/journal
      - name: foo
        - name: runlog
          mountPath: /run/log/journal
          readOnly: true
      - name: runlog
          path: /run/log/journal
  • Use systemd-journal to read the logs
    require 'systemd/journal'
    journal =
    journal.filter(syslog_identifier: 'kernel') { |entry| puts entry.message }

Chef install google-cloud-sdk without package manager

A tiny chef snipped to install gcloud without using a package manager (to get the latest version without waiting)

gcloud_version = node["foo"]["google-cloud-sdk_version"]
gcloud_file = "google-cloud-sdk-#{gcloud_version}-linux-x86_64.tar.gz"
gcloud_folder = ""
gcloud_installer = ""
execute "gcloud_install" do
  # clean up ... download installer but select the version we want ... install ... link
  command "rm -rf $CLOUDSDK_INSTALL_DIR/google-cloud-sdk && curl #{gcloud_installer} | sed 's;__SDK_URL_DIR=.*;__SDK_URL_DIR=#{gcloud_folder};' | sed 's/__SDK_TGZ=.*/__SDK_TGZ=#{gcloud_file}/' | bash && ln -sf $CLOUDSDK_INSTALL_DIR/google-cloud-sdk/bin/gcloud /usr/local/bin/gcloud"
    "CLOUDSDK_INSTALL_DIR" => "/opt", # prefix
  not_if { `true && gcloud -v`.include?(gcloud_version) } # ~FC048