jaeger-client-socat-redirector.service

# Copyright (c) 2019 Intel Corporation
#
# SPDX-License-Identifier: Apache-2.0

#---------------------------------------------------------------------
# Description: Systemd unit to redirect Jaeger client UDP traffic from
#   the Kata Containers agent to a Jaeger agent process running on the
#   host. This is achieved by creating a VSOCK bridge.
#
# Note: The "other side" of the VSOCK bridge (outside the virtual
#   machine) is handled by the vsock-to-udp-server.sh script.
#---------------------------------------------------------------------

[Unit]
Description=Jaeger client VM to host redirector

[Service]
# Default Jaeger agent UDP port a Jaeger client should send trace traffic to.
#
# See:
#
# - https://jaegertracing.io/docs/getting-started
# - https://jaegertracing.io/docs/architecture
Environment=jaeger_port=6831
# The horrid hex string below represents the VSOCK address with:
#
# - CID 2 (reserved for HOST)
# - port 6831
#
# This hex string is required to be passed to socat(1) since at the time of
# writing socat version 1.7.3.2 does not understand VSOCK sockets
# (but does provide this method to overcome this limitation).
#
# See:
#
# - https://gist.github.com/mcastelino/9a57d00ccf245b98de2129f0efe39857#using-specific-ports
# - http://www.dest-unreach.org/socat/doc/socat-genericsocket.html
Environment=host_vsock_addr=x00x00xafx1ax00x00x02x00x00x00x00x00x00x00
Type=simple
ExecStart=/bin/socat -u "udp-listen:${jaeger_port},reuseaddr,fork" "socket-connect:40:0:${host_vsock_addr}"
LimitNOFILE=infinity
Restart=on-failure

[Install]
WantedBy=kata-agent.service