Vault Side Kick
Summary
Vault Sidekick is a add-on container which can be used as a generic entry-point for interacting with Hashicorp Vault service, retrieving secrets (both static and dynamic) and PKI certs. The sidekick will take care of renewal's and extension of leases for you and renew the credentials in the specified format for you.
Usage
$ sudo docker run --rm quay.io/ukhomeofficedigital/vault-sidekick:v0.3.3 -help
Usage of /vault-sidekick:
-alsologtostderr
log to standard error as well as files
-auth string
a configuration file in json or yaml containing authentication arguments
-ca-cert string
the path to the file container the CA used to verify the vault service
-cn value
a resource to retrieve and monitor from vault
-dryrun
perform a dry run, printing the content to screen
-exec-timeout duration
the timeout applied to commands on the exec option (default 1m0s)
-format string
the auth file format (default "default")
-log_backtrace_at value
when logging hits line file:N, emit a stack trace
-log_dir string
If non-empty, write log files in this directory
-logtostderr
log to standard error instead of files
-one-shot
retrieve resources from vault once and then exit
-output string
the full path to write resources or VAULT_OUTPUT (default "/etc/secrets")
-renew-token
renew vault token according to its ttl
-stats duration
the interval to produce statistics on the accessed resources (default 1h0m0s)
-stderrthreshold value
logs at or above this threshold go to stderr
-tls-skip-verify
whether to check and verify the vault service certificate
-v value
log level for V logs
-vault string
url the vault service or VAULT_ADDR (default "https://127.0.0.1:8200")
-version
show the vault-sidekick version
-vmodule value
comma-separated list of pattern=N settings for file-filtered logging
-request-token
request an authentication token from vault and exit
Building
There is a Makefile in the base repository, so assuming you have make and go: $ make
Example Usage
The below is taken from a Kubernetes pod specification;
spec:
containers:
- name: vault-side-kick
image: quay.io/ukhomeofficedigital/vault-sidekick:v0.3.3
args:
- -output=/etc/secrets
- -cn=pki:project1/certs/example.com:common_name=commons.example.com,revoke=true,update=2h
- -cn=secret:secret/db/prod/username:file=.credentials
- -cn=secret:secret/db/prod/password:retries=true
- -cn=secret:secret/data/db/dev/username:file=.kv2credentials
- -cn=aws:aws/creds/s3_backup_policy:file=.s3_creds
volumeMounts:
- name: secrets
mountPath: /etc/secrets
The above equates to:
- Write all the secrets to the /etc/secrets directory
- Retrieve a dynamic certificate pair for me, with the common name: 'commons.example.com' and renew the cert when it expires automatically
- Retrieve the two static secrets /db/prod/{username,password} and write them to .credentials and password.secret respectively
- Retrieve the latest version of static secret /db/dev/username from a v2 kv store and write it to .kv2credentials
- Apply the IAM policy, renew the policy when required and file the API tokens to .s3_creds in the /etc/secrets directory
- Read the template at /etc/templates/db.tmpl, produce the content from Vault and write to /etc/credentials file
Authentication
An authentication file can be specified in either yaml of json format which contains a method field, indicating one of the authentication methods provided by vault i.e. userpass, token, github etc and then followed by the required arguments for that plugin.
If the required arguments for that plugin are not contained in the authentication file, fallbacks from environment variables are used.
Environment variables are prefixed with VAULT_SIDEKICK
, i.e. VAULT_SIDEKICK_USERNAME
, VAULT_SIDEKICK_PASSWORD
.
Kubernetes Authentication
The Kubernetes auth plugin supports the following environment variables:
VAULT_SIDEKICK_ROLE
- The Vault role name against which to authenticate (REQUIRED)VAULT_K8S_LOGIN_PATH
- If your Kubernetes auth backend is mounted at a path other thankubernetes/
you will need to set this. Default/v1/auth/kubernetes/login
VAULT_K8S_TOKEN_PATH
- If you mount in-pod service account tokens to a non-default path, you will need to set this. Default/var/run/secrets/kubernetes.io/serviceaccount/token
AppRole Authentication
The AppRole auth plugin supports the following configurations / environment variables:
role_id
/VAULT_SIDEKICK_ROLE_ID
- The approle role_id to authenticate with (REQUIRED)secret_id
/VAULT_SIDEKICK_SECRET_ID
- The approle secret_id to authenticate with (REQUIRED)login_path
/VAULT_APPROLE_LOGIN_PATH
- If your AppRole auth backend is mounted at a path other thanapprole/
you will need to set this. Default/v1/auth/approle/login
Secret Renewals
The default behaviour of vault-sidekick is not to renew a lease, but to retrieve a new secret and allow the previous to expire, in order ensure the rotation of secrets. If you don't want this behaviour on a resource you can override using resource options. For exmaple, your using the mysql dynamic secrets, you want to renew the secret not replace it
[jest@starfury vault-sidekick]$ build/vault-sidekick -cn=mysql:mysql/creds/my_database:fmt=yaml,renew=true
or an iam policy renewed every hour
[jest@starfury vault-sidekick]$ build/vault-sidekick -cn=aws:aws/creds/policy:fmt=yaml,renew=true,update=1h
Or you want to rotate the secret every 1h and revoke the previous one
[jest@starfury vault-sidekick]$ build/vault-sidekick -cn=aws:project/creds/my_s3_bucket:fmt=yaml,update=1h,revoke=true
The format is;
-cn=RESOURCE_TYPE:PATH:OPTIONS
The sidekick supports the following resource types: mysql, postgres, database, pki, aws, gcp, secret, cubbyhole, raw, cassandra and transit
Environment Variable Expansion
The resource paths can contain environment variables which the sidekick will resolve beforehand. A use case being, using a environment or domain within the resource e.g -cn=secret:secrets/myservice/${ENV}/config:fmt=yaml
Output Formatting
The following output formats are supported: json, yaml, ini, txt, cert, csv, bundle, env, credential, aws
Using the following at the demo secrets
[jest@starfury vault-sidekick]$ vault write secret/password this=is demo=value nothing=more
Success! Data written to: secret/password
[jest@starfury vault-sidekick]$ vault read secret/password
Key Value
lease_id secret/password/7908eceb-9bde-e7de-23da-96131505214a
lease_duration 2592000
lease_renewable false
demo value
nothing more
this is
In order to change the output format:
[jest@starfury vault-sidekick]$ build/vault-sidekick -cn=secret:secret/password:fmt=ini -logtostderr=true -dry-run
[jest@starfury vault-sidekick]$ build/vault-sidekick -cn=secret:secret/password:fmt=json -logtostderr=true -dry-run
[jest@starfury vault-sidekick]$ build/vault-sidekick -cn=secret:secret/password:fmt=yaml -logtostderr=true -dry-run
Format: 'cert' is less of a format of more file scheme i.e. is just extracts the 'certificate', 'issuing_ca' and 'private_key' and creates the three files FILE.{ca,key,crt}. The bundle format is very similar in the sense it similar takes the private key and certificate and places into a single file. 'credential' will attempt to decode a GCP credential file and 'aws' will write an AWS credentials file.
Resource Options
- file: (filaname) by default all file are relative to the output directory specified and will have the name NAME.RESOURCE; the fn options allows you to switch names and paths to write the files
- mode: (mode) overrides the default file permissions of the secret from 0664
- create: (create) create the resource
- update: (update) override the lease time of this resource and get/renew a secret on the specified duration e.g 1m, 2d, 5m10s
- renew: (renewal) override the default behavour on this resource, renew the resource when coming close to expiration e.g true, TRUE
- delay: (renewal-delay) delay the revoking the lease of a resource for x period once time e.g 1m, 1h20s
- revoke: (revoke) revoke the old lease when you get retrieve a old one e.g. true, TRUE (default to allow the lease to expire and naturally revoke)
- fmt: (format) allows you to specify the output format of the resource / secret, e.g json, yaml, ini, txt
- exec (execute) execute's a command when resource is updated or changed
- retries: (retries) the maximum number of times to retry retrieving a resource. If not set, resources will be retried indefinitely
- jitter: (jitter) an optional maximum jitter duration. If specified, a random duration between 0 and
jitter
will be subtracted from the renewal time for the resource - ttl: (ttl) an optional ttl to use with the Vault PKI backend, should be specified as per the Vault PKI backend ttl resource (eg. 24h for one day). Hours are the largest suffix.