Templates in nomad jobs make use of the vault token defined in
the vault stanza when issuing credentials like client certificates.
When using change_mode "noop" in the vault stanza, consul-template
is not informed in case a vault token is re-issued (which can
happen from time to time for various reasons, as described
in https://www.nomadproject.io/docs/job-specification/vault).
As a result, consul-template will keep using the old vault token
to renew credentials and - once the token expired - stop renewing
credentials. The symptom of this problem is a vault_token
file that is newer than the issued credential (e.g., TLS certificate)
in a job's /secrets directory.
This change corrects this, so that h.updater.updatedVaultToken(token)
is called, which will inform stakeholders about the new
token and make sure, the new token is used by consul-template.
Example job template fragment:
vault {
policies = ["nomad-job-policy"]
change_mode = "noop"
}
template {
data = <<-EOH
{{ with secret "pki_int/issue/nomad-job"
"common_name=myjob.service.consul" "ttl=90m"
"alt_names=localhost" "ip_sans=127.0.0.1"}}
{{ .Data.certificate }}
{{ .Data.private_key }}
{{ .Data.issuing_ca }}
{{ end }}
EOH
destination = "${NOMAD_SECRETS_DIR}/myjob.crt"
change_mode = "noop"
}
This fix does not alter the meaning of the three change modes of vault
- "noop" - Take no action
- "restart" - Restart the job
- "signal" - send a signal to the task
as the switch statement following line 232 contains the necessary
logic.
It is assumed that "take no action" was never meant to mean "don't tell
consul-template about the new vault token".
Successfully tested in a staging cluster consisting of multiple
nomad client nodes.
