Batfish introduction

Batfish is a configuration compliance tool, amongst other things.

Here are my notes on getting setup with batfish with JunOS configuration. I’m using offline configs (think: RANCID or Oxidized config backups).

Batfish introduction

Getting your JunOS config ready

• Gather your configuration from either RANCID or jlogin (Or whatever you have):

    jlogin -c "show configuration" ${ROUTER} &> ${ROUTER}.cfg ; 
    dos2unix ${ROUTER}.cfg; 
    cat ${ROUTER}.cfg | gsed -n '/^\#\#\ Last/,//p' | grep -vE '(\@.*\>|^Connection)' > batfish/snapshots/configs/${ROUTER}.cfg

Getting batfish setup

• Follow install instructions on Their GitHub page
• If you get a failure to execute command batfish_build_all, ensure you source tools/common.sh
• You can do your first run with allinone -runmode interactive

Importing your configuration

• You will need a directory (batfish/snapshots in my example) to store files.

    $ tree | grep -v cfg
    .
    ├── configs
    └── node_rules.json

    1 directory, 119 files

• Place the configurations into batfish/snapshots/configs
• Create a node_rules.json (Example 1, Example 2). Place this in batfish/snapshots
• From here, you’ll want to import your configuration (This will take some time)

    init-snapshot batfish/snapshots/ MY_IMPORTED_NETWORK

Checking for import issues

• First run, I encountered a parse issue. Here is some useful commands that helped me find it :

    # Get import information
    get initinfo
    # Set the log levels to debug
    set-batfish-loglevel debug
    set-loglevel debug
    # Delete the named import and re-import it
    del-snapshot MY_IMPORTED_NETWORK
    init-snapshot batfish/snapshots/ MY_IMPORTED_NETWORK

- 

Sample commands to start to parse your data

• Taken from here and here

    # See what's connected to what
    get neighbors
    get neighbors neighborTypes=["ibgp"]
    
    # See a list of nodes, filtered by regex REGEX_GOES_HERE
    get nodes summary=True, nodeRegex='REGEX_GOES_HERE'
    
    # Find all interfaces which have a description 'Peering', display their description only (Query uses JSONPath syntax)
    get nodespath paths=[{"path":"$.nodes[*].interfaces[*][?(@.description =~ /.*Peering.*/i)].description", "suffix":True }]