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Thomas Mangin edited this page Nov 17, 2025 · 5 revisions

Migration from ExaBGP 4.x to 5.0.0

Complete guide for upgrading from ExaBGP 4.x to 5.0.0

⚠️ BREAKING CHANGES: ExaBGP 5.0.0 introduces breaking changes from 4.x

ExaBGP 5.0.0 is a major release (November 2024) with 871 commits and significant improvements, but requires careful migration planning.

Key Changes:

  • ❌ Python 2 completely removed (Python 3.8+ required)
  • ⚠️ JSON API format changes (AS-PATH, BGP-LS fields)
  • ⚠️ Configuration syntax changes (route-refresh, FlowSpec)
  • ⚠️ Deprecated features removed (Prefix-SID Type-2/4)
  • ✅ Major protocol enhancements (SRv6, BGP-MUP, RFC 9072)
  • ✅ Security fixes (TOCTOU vulnerability)

Table of Contents

Overview

Release: ExaBGP 5.0.0 (November 2024)

Severity: 🔴 HIGH - Breaking changes require careful migration

Timeline: ExaBGP 5.0.0 is the new LTS (Long-Term Support). ExaBGP 4.x enters maintenance mode (critical fixes only, no new features).

Changes: 871 commits, 920 files changed, largest release in ExaBGP history

Should You Upgrade?

✅ YES - Upgrade to 5.0.0 If:

  • ✅ You need SRv6 (Segment Routing over IPv6) support
  • ✅ You need BGP-MUP (Mobile User Plane) support
  • ✅ You want the TOCTOU security vulnerability fix
  • ✅ You need RFC 9072 (Extended Optional Parameters Length)
  • ✅ You want latest protocol features and improvements
  • ✅ You can test thoroughly before production deployment

⏸️ WAIT - Stay on 4.x If:

  • ⏸️ You cannot test the migration thoroughly
  • ⏸️ You're using JSON API parsers (need updates for AS-PATH format)
  • ⏸️ You're using BGP-LS with JSON (field names changed)
  • ⏸️ You're using Prefix-SID Type-2 or Type-4 (removed in 5.0.0)
  • ⏸️ Your systems use Python < 3.8

Recommendation: Test 5.0.0 in staging first. ExaBGP 4.x remains a stable LTS option.

What Changed

Breaking Changes Summary

Area Change Impact
Python 3.8+ required (2.x removed) 🔴 CRITICAL - System upgrade needed
JSON API AS-PATH format changed 🔴 HIGH - Parser updates required
BGP-LS JSON Field names changed 🔴 HIGH - Parser updates required
Configuration route-refresh, FlowSpec syntax 🟡 MEDIUM - Config updates needed
Prefix-SID Type-2/4 removed 🟡 MEDIUM - Only if using these types
tcp.once Replaced by tcp.attempts 🟢 LOW - Syntax change only

New Major Features

  • ✅ SRv6 - Complete Segment Routing over IPv6 support
  • ✅ BGP-MUP - Mobile User Plane SAFI (draft-mpmz-bess-mup-safi-02)
  • ✅ RFC 9072 - Extended Optional Parameters Length
  • ✅ RFC 6514 - MCAST-VPN Route Types 5, 6, 7
  • ✅ ACK Runtime Control - disable-ack, enable-ack, silence-ack commands
  • ✅ Neighbor Wildcards - neighbor * announce ... syntax
  • ✅ Security Fixes - TOCTOU race condition fixed
  • ✅ Official Docker Images - ghcr.io/exa-networks/exabgp:5.0.0

Breaking Changes

Python Version Requirements

ExaBGP 4.x

  • ✅ Python 2.7 (deprecated but supported)
  • ✅ Python 3.6+

ExaBGP 5.0.0

  • ❌ Python 2.x completely removed
  • ✅ Python 3.8+ minimum (3.9+ recommended)
  • ✅ Python 3.13 tested and supported

Migration Action

# Check your Python version
python3 --version

# If < 3.8, upgrade Python first
# Ubuntu/Debian:
sudo apt install python3.9

# RHEL/CentOS:
sudo dnf install python39

# macOS:
brew install [email protected]

Impact: If you're on Python 2.7 or 3.6/3.7, you must upgrade Python before upgrading ExaBGP.

JSON API Format Changes

1. AS-PATH Format Changed

ExaBGP 4.x (Old Format):

{
  "type": "update",
  "neighbor": {
    "address": {
      "local": "192.168.1.1",
      "peer": "192.168.1.2"
    }
  },
  "attribute": {
    "as-path": [65001, 65002, 65003]
  }
}

ExaBGP 5.0.0 (New Format):

{
  "type": "update",
  "neighbor": {
    "address": {
      "local": "192.168.1.1",
      "peer": "192.168.1.2"
    }
  },
  "attribute": {
    "as-path": "[ 65001 65002 65003 ]"
  }
}

Important: The string format encodes AS_PATH segment types using different bracket styles:

Brackets Segment Type Description
( ) AS_SEQUENCE Ordered list of ASNs (most common)
[ ] AS_SET Unordered set of ASNs (route aggregation)
{( )} CONFED_SEQUENCE Confederation sequence
{[ ]} CONFED_SET Confederation set

Example with multiple segment types:

{
  "attribute": {
    "as-path": "[ 65001 65002 ] ( 65003 65004 65005 )"
  }
}

This represents an AS_SET [65001, 65002] followed by an AS_SEQUENCE (65003, 65004, 65005).

Migration Action: Update your JSON parsers to handle AS-PATH as a string instead of an array.

Python Example (Simple - treats all as sequence):

# Old 4.x parser
as_path = data['attribute']['as-path']  # List[int]
for asn in as_path:
    print(asn)

# New 5.0.0 parser (simple - extracts all ASNs)
as_path_str = data['attribute']['as-path']  # str: "[ 65001 65002 ]"
as_path = [int(asn) for asn in as_path_str.replace('[', '').replace(']', '').replace('(', '').replace(')', '').replace('{', '').replace('}', '').split()]
for asn in as_path:
    print(asn)

Python Example (Advanced - preserves segment types):

import re

def parse_as_path(as_path_str):
    """Parse AS_PATH string preserving segment types"""
    segments = []

    # Match each segment with its bracket type
    pattern = r'(\{?\[|\{?\()\s*([\d\s]+)\s*(\]?\}|\)?\})'
    for match in re.finditer(pattern, as_path_str):
        open_bracket = match.group(1)
        asns = [int(asn) for asn in match.group(2).split()]

        # Determine segment type
        if open_bracket == '[':
            segment_type = 'AS_SET'
        elif open_bracket == '(':
            segment_type = 'AS_SEQUENCE'
        elif open_bracket == '{[':
            segment_type = 'CONFED_SET'
        elif open_bracket == '{(':
            segment_type = 'CONFED_SEQUENCE'

        segments.append({'type': segment_type, 'asns': asns})

    return segments

# Example
as_path_str = "[ 65001 65002 ] ( 65003 65004 )"
segments = parse_as_path(as_path_str)
# Result: [
#   {'type': 'AS_SET', 'asns': [65001, 65002]},
#   {'type': 'AS_SEQUENCE', 'asns': [65003, 65004]}
# ]

2. BGP-LS Field Name Changes

ExaBGP 4.x (Old):

{
  "bgp-ls": {
    "sr_capability_flags": "0x80",
    "interface-address": ["192.168.1.1"],
    "neighbor-address": ["192.168.1.2"]
  }
}

ExaBGP 5.0.0 (New):

{
  "bgp-ls": {
    "sr-capability-flags": "0x80",
    "interface-addresses": ["192.168.1.1"],
    "neighbor-addresses": ["192.168.1.2"]
  }
}

Changes:

  • sr_capability_flags → sr-capability-flags (underscore to hyphen)
  • interface-address → interface-addresses (singular to plural)
  • neighbor-address → neighbor-addresses (singular to plural)
  • Extended Communities: Removed L prefix from target field

Migration Action: Update BGP-LS JSON parsers to use new field names.

Configuration Syntax Changes

1. Route Refresh Command

ExaBGP 4.x:

# Old syntax (space separator)
route refresh

ExaBGP 5.0.0:

# New syntax (hyphenated)
route-refresh

Migration Action: Update any scripts or configurations using route refresh to route-refresh.

2. FlowSpec Fragment Syntax

ExaBGP 4.x:

flow route {
    match {
        fragment not-a-fragment;
    }
    then {
        discard;
    }
}

ExaBGP 5.0.0:

flow route {
    match {
        fragment !is-fragment;
    }
    then {
        discard;
    }
}

Migration Action: Update FlowSpec configurations:

  • not-a-fragment → !is-fragment

3. TCP Connection Attempts

ExaBGP 4.x:

neighbor 192.168.1.1 {
    tcp {
        once true;  # Try to connect only once
    }
}

ExaBGP 5.0.0:

neighbor 192.168.1.1 {
    tcp {
        attempts 1;  # Number of connection attempts (0 = infinite)
    }
}

Migration Action: Replace tcp.once with tcp.attempts.

Deprecated Features Removed

1. Prefix-SID Type-2 and Type-4 Removed

ExaBGP 4.x:

  • ✅ Prefix-SID Type-1 (Label-Index)
  • ⚠️ Prefix-SID Type-2 (deprecated)
  • ✅ Prefix-SID Type-3 (Originator SRGB)
  • ⚠️ Prefix-SID Type-4 (deprecated)

ExaBGP 5.0.0:

  • ✅ Prefix-SID Type-1 (Label-Index)
  • ❌ Prefix-SID Type-2 REMOVED
  • ✅ Prefix-SID Type-3 (Originator SRGB)
  • ❌ Prefix-SID Type-4 REMOVED
  • ✅ Prefix-SID Type-5 (NEW - SRv6 Locator)
  • ✅ Prefix-SID Type-6 (NEW - SRv6 Endpoint Behavior)

Migration Action: If using Type-2 or Type-4, migrate to Type-1/3 or new Type-5/6.

2. Hostname Capability Auto-Send

ExaBGP 4.x:

  • Hostname (FQDN) capability sent by default

ExaBGP 5.0.0:

  • Hostname capability NOT sent by default
  • Must explicitly enable if needed

Migration Action: If you rely on hostname capability, explicitly enable it:

neighbor 192.168.1.1 {
    capability {
        hostname enable;  # Explicitly enable
    }
}

3. Syslog Facility Changed

ExaBGP 4.x:

  • Syslog facility: syslog

ExaBGP 5.0.0:

  • Syslog facility: daemon

Migration Action: Update syslog filters if you're parsing ExaBGP logs.

New Features in 5.0.0

Protocol Extensions

SRv6 (Segment Routing over IPv6)

Complete support for SRv6:

# Announce SRv6 route with End.X SID
announce route 2001:db8::/48 next-hop 2001:db8::1 \
    prefix-sid srv6-l3-service 2001:db8:100::1 endpoint-behavior End.DT6

New SRv6 TLVs:

  • ✅ SRv6 Capabilities TLV
  • ✅ SRv6 Locator TLV
  • ✅ SRv6 End.X SID TLV
  • ✅ SRv6 LAN End.X SID TLV
  • ✅ SRv6 Endpoint Behavior TLV
  • ✅ SRv6 SID NLRI

See: SRv6 and MUP Documentation

BGP-MUP (Mobile User Plane)

Support for draft-mpmz-bess-mup-safi-02:

# Announce MUP route
announce mup isd 100.64.0.1 session-transformed 2001:db8:mup::1

Features:

  • ✅ MUP SAFI
  • ✅ MUP Extended Community
  • ✅ Source Address in MUP Type 1 ST Route
  • ✅ Improved MUP Type2SessionTransformedRoute encoding

RFC Implementations

  • ✅ RFC 9072 - Extended Optional Parameters Length for BGP OPEN
  • ✅ RFC 6514 - MCAST-VPN Route Types 5, 6, 7
  • ✅ RFC 8203 - Shutdown communication improvements
  • ✅ draft-abraitis-bgp-version-capability - Software version capability

API Enhancements

ACK Runtime Control (NEW)

ExaBGP 4.x:

  • ACK control via environment variable only

ExaBGP 5.0.0:

  • ✨ NEW: Runtime control commands
# Disable ACK for this connection
sys.stdout.write("disable-ack\n")
sys.stdout.flush()

# Re-enable ACK
sys.stdout.write("enable-ack\n")
sys.stdout.flush()

# Temporarily suppress ACK messages
sys.stdout.write("silence-ack\n")
sys.stdout.flush()

See: API Overview - ACK Feature

Neighbor Wildcards (NEW)

# Announce to ALL neighbors
sys.stdout.write("neighbor * announce route 100.10.0.0/24 next-hop self\n")
sys.stdout.flush()

CLI Improvements

# Multiple concurrent CLI instances
exabgp --pipename cli1 --run /etc/exabgp/exabgp.conf

# JSON output for neighbor info
exabgpcli show neighbor json

Healthcheck Enhancements

New options:

# Set IP addresses on physical interfaces
exabgp healthcheck --ip-ifname

# Debounce flapping routes
exabgp healthcheck --debounce 5

# Exact loopback interface label matching
exabgp healthcheck --label-exact-match

Features:

  • Path ID support for advertised routes
  • Per-neighbor route filtering
  • Automatic announcement of user-defined loopback IPs

Container Support

Official Docker images:

# Pull official image
docker pull ghcr.io/exa-networks/exabgp:5.0.0

# Run ExaBGP in container
docker run -d --name exabgp \
  -v /etc/exabgp:/etc/exabgp \
  ghcr.io/exa-networks/exabgp:5.0.0

See: Docker Deployment Guide

Security Fixes

  • ✅ TOCTOU Vulnerability Fixed - Time-of-Check-Time-of-Use race condition in configuration parser
  • ✅ Configuration Reload Fix (#1340) - API process state consistency

Migration Steps

Step 1: Verify Python Version

# Check Python version
python3 --version

# Must be 3.8 or higher
# Recommended: 3.9 or higher

If Python < 3.8, upgrade Python first.

Step 2: Test Configuration Syntax

# Backup current config
cp /etc/exabgp/exabgp.conf /etc/exabgp/exabgp.conf.4.x.bak

# Update config syntax if needed:
# - route refresh → route-refresh
# - not-a-fragment → !is-fragment
# - tcp.once → tcp.attempts

# Test configuration
exabgp --test /etc/exabgp/exabgp.conf

Step 3: Update JSON API Parsers

If using JSON encoder:

# Update AS-PATH parsing
# OLD: as_path = data['attribute']['as-path']  # List[int]
# NEW: as_path_str = data['attribute']['as-path']  # str

# Update BGP-LS field names
# OLD: sr_capability_flags, interface-address, neighbor-address
# NEW: sr-capability-flags, interface-addresses, neighbor-addresses

Step 4: Check for Deprecated Features

# Search config for removed features
grep -E "Type-2|Type-4" /etc/exabgp/exabgp.conf

# Search for tcp.once
grep "tcp.once" /etc/exabgp/exabgp.conf

If found, update to supported alternatives.

Step 5: Install ExaBGP 5.0.0

# From PyPI
pip3 install --upgrade exabgp==5.0.0

# Or from source
git clone https://github.com/Exa-Networks/exabgp.git
cd exabgp
git checkout 5.0.0
pip3 install .

Step 6: Test in Staging

# Start ExaBGP with your updated config
exabgp /etc/exabgp/exabgp.conf

# Monitor logs for errors
tail -f /var/log/exabgp.log

# Verify BGP sessions establish
exabgpcli show neighbor summary

Step 7: Validate API Programs

# Test your API programs
# - Verify ACK handling still works
# - Verify JSON parsing (if using JSON encoder)
# - Test route announcements/withdrawals
# - Check error handling

Step 8: Deploy to Production

Only after thorough testing:

# Deploy to production
# Monitor closely for first 24 hours
# Have rollback plan ready

Testing Your Migration

Configuration Testing Checklist

  • Configuration syntax valid: exabgp --test /etc/exabgp/exabgp.conf
  • No deprecated syntax (route refresh, not-a-fragment, tcp.once)
  • No Prefix-SID Type-2 or Type-4 usage
  • Hostname capability explicitly enabled if needed

API Testing Checklist

  • JSON parser handles AS-PATH as string
  • BGP-LS JSON parser uses new field names
  • ACK handling still works
  • Route announcements work
  • Route withdrawals work
  • Error handling works

Integration Testing Checklist

  • BGP sessions establish successfully
  • Routes announced correctly
  • Health checks work (if using healthcheck module)
  • Logs parsed correctly (syslog facility changed to daemon)
  • Monitoring/alerting still works

Rollback Plan

If issues occur, rollback to 4.x:

# 1. Stop ExaBGP 5.0.0
systemctl stop exabgp

# 2. Restore 4.x configuration
cp /etc/exabgp/exabgp.conf.4.x.bak /etc/exabgp/exabgp.conf

# 3. Reinstall 4.x
pip3 install exabgp==4.2.22

# 4. Restart ExaBGP
systemctl start exabgp

# 5. Verify sessions
exabgpcli show neighbor summary

Important: Keep your 4.x configuration backed up until 5.0.0 is validated in production.

Common Issues

Issue 1: Python Version Too Old

Symptom:

SyntaxError: invalid syntax

Cause: Python < 3.8

Solution:

# Upgrade Python to 3.8+
# Ubuntu/Debian:
sudo apt install python3.9
pip3.9 install exabgp==5.0.0

Issue 2: JSON Parser Fails on AS-PATH

Symptom:

TypeError: 'str' object is not iterable

Cause: AS-PATH is now string, not array

Solution:

# Update parser
as_path_str = data['attribute']['as-path']  # str: "[ 65001 65002 ]"
as_path = [int(asn) for asn in as_path_str.strip('[]').split()]

Issue 3: BGP-LS JSON Fields Missing

Symptom:

KeyError: 'sr_capability_flags'

Cause: Field names changed (underscore → hyphen, singular → plural)

Solution:

# Update field names
sr_flags = data['bgp-ls']['sr-capability-flags']  # Changed
iface_addrs = data['bgp-ls']['interface-addresses']  # Changed

Issue 4: Configuration Syntax Errors

Symptom:

Error: unknown command 'route refresh'

Cause: Syntax changed to route-refresh

Solution:

# Update config
sed -i 's/route refresh/route-refresh/g' /etc/exabgp/exabgp.conf

Issue 5: Prefix-SID Type-2/4 Errors

Symptom:

Error: Prefix-SID Type-2 not supported

Cause: Type-2 and Type-4 removed in 5.0.0

Solution: Migrate to Type-1, Type-3, Type-5, or Type-6

Version Compatibility Matrix

Feature 4.x 5.0.0 Compatible?
Configuration 4.x syntax 5.0.0 syntax ⚠️ Mostly (minor changes)
Text API Text encoder Text encoder ✅ Compatible
JSON API 4.x JSON 5.0.0 JSON ❌ AS-PATH changed
Python 2.7, 3.6+ 3.8+ only ❌ Python 2 removed
ACK Feature ✅ (env var only) ✅ (+ runtime control) ✅ Compatible
FlowSpec 4.x syntax 5.0.0 syntax ⚠️ Fragment syntax changed
Prefix-SID Type 1-4 Type 1,3,5,6 ❌ Type 2/4 removed

Upgrade Decision Matrix

Your Situation Recommendation Action
Python < 3.8 ⏸️ Wait Upgrade Python first
Using JSON API ⚠️ Test carefully Update parsers before upgrading
Using BGP-LS JSON ⚠️ Test carefully Update field names in parsers
Using Text API only ✅ Safe to upgrade Test config syntax
Need SRv6 ✅ Upgrade SRv6 only in 5.0.0
Need BGP-MUP ✅ Upgrade BGP-MUP only in 5.0.0
Security-conscious ✅ Upgrade TOCTOU fix in 5.0.0
Production-critical ⏸️ Test first Validate in staging

Recommendation

For New Deployments: Use ExaBGP 5.0.0 (latest stable)

For Existing 4.x Users:

  1. ✅ Test thoroughly in staging environment
  2. ⚠️ Update JSON parsers if using JSON encoder
  3. ⚠️ Update configurations for syntax changes
  4. ✅ Upgrade Python to 3.8+ if needed
  5. ✅ Deploy to production with rollback plan ready

ExaBGP 5.0.0 is now the LTS release. ExaBGP 4.x enters maintenance mode (critical fixes only).

See Also

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