Deploying the IAM VOMS attribute authority
The IAM VOMS attribute authority
The IAM VOMS attribute authority (AA) provide backward-compatible VOMS support for a Virtual Organization managed with IAM.
Deployment architecture
The VOMS attribute authority can access the IAM database and encode IAM groups and other attributes in a standard VOMS attribute certificate. This means in practice that IAM can act both as an OAuth/OpenID Connect authorization server and as a VOMS server for a given organization. TLS termination and client VOMS atttribute certificate parsing and validation is delegated to an NGINX VOMS module, which can de deployed as a sidecar service that just protects the VOMS AA or also in front of the IAM backend application. The two scenarios are depicted above.
In order to deploy a VOMS attribute authority, you can use the following docker images:
cnafsd/nginx-httpg-voms, for the NGINX VOMS module (which replaces OpenResty VOMS)indigoiam/voms-aa:v1.10.0, for the VOMS AA service
Deployment from packages is not currently supported for the VOMS attribute authority.
NGINX VOMS module configuration
The NGINX VOMS module requires:
- IGTF trust anchors properly configured; see the EGI trust anchors container container
- the
vomsdirfolder, with the VOMS LSC configuration generated starting from the VOMS attribute authority X.509 credential
VOMS LSC configuration
Let’s assume that the IAM VOMS AA will answer on voms.test.example for the VO
example.vo, to generate the LSC you need to get the subject and issuer of the
VOMS AA X.509 credential and put them in a file named as the fully qualified
domain name of the VOMS attribute authority with the .lsc extension.
The following command does exactly that (X509_VOMS_DIR can be set to any
directory where you have writing privileges):
> mkdir -p ${X509_VOMS_DIR}/example.vo
> openssl x509 -in voms_local_io.cert.pem -noout -subject -issuer -nameopt compat | \
gsed -e 's/^subject=//' -e 's/^issuer=//' > \
${X509_VOMS_DIR}/example.vo/voms.test.example.lsc
For an example nginx configuration, see the VOMS AA docker compose configuration.
VOMS AA configuration
The VOMS AA is a spring boot application that shares the persistence layer implementation with IAM, and as such can inspect the IAM database.
An example configuration for the VOMS AA service is given below, with comments to explain the meaning of the parameters:
server:
address: 0.0.0.0 # bind on all IP addresses
port: 8080 # listen on port 8080
use-forward-headers: true # assume you're behind a reverse proxy
# change the default http header size limit to accomodate VOMS information passed
# down by the ngx-voms server
max-http-header-size: 16000
spring:
main:
banner-mode: "off"
jpa:
open-in-view: true
## Database connection parameters
datasource:
dataSourceClassName: com.mysql.jdbc.jdbc2.optional.MysqlDataSource
url: jdbc:mysql://${IAM_DB_HOST}:${IAM_DB_PORT:3306}/${IAM_DB_NAME}?useLegacyDatetimeCode=false&serverTimezone=UTC&useSSL=false
username: ${IAM_DB_USERNAME}
password: ${IAM_DB_PASSWORD}
flyway:
enabled: false
voms:
tls:
# The VOMS AA certificate
certificate-path: /certs/hostcert.pem
# The VOMS AA certificate key
private-key-path: /certs/hostkey.pem
# Where to look for X.509 trust anchors
trust-anchors-dir: /etc/grid-security/certificates
# How often should trust anchors (and CRLs) be refreshed
# The default value is 86400
trust-anchors-refresh-interval-secs: 14400
aa:
# The VOMS attribute authority host
host: voms.example
# The VOMS attribute authority port. Note that this is the port on
# the reverse proxy, not the local service port
port: 443
# The VOMS VO name
vo-name: ${VOMS_AA_VO}
# Use FQAN legacy encoding, i.e.,
# /voms/Role=NULL/Capability=NULL
# instead of
# /voms
# The default value is false
use-legacy-fqan-encoding: true
# The VOMS proxy lifetime in seconds
# The default value is 12 hours
max-ac-lifetime-in-seconds: 43200
# The optional group label
# The default value is wlcg.optional-group
# This option specify the label to be assigned for custom VOMS roles.
# E.g.: "pilot" is a subgroup of the "vo-name" IAM group. If it is made
# "optional group" in IAM via the dedicated button, users belonging to
# it can request the "pilot" VOMS role.
optional-group-label: voms.role
For an example configuration, see the VOMS AA docker compose file.