Unit with After=network-online.target starts up before an IP is on the interface

[MohammadKarimi23]

Bug

Container Linux Version

NAME="Container Linux by CoreOS"
ID=coreos
VERSION=1298.7.0
VERSION_ID=1298.7.0
BUILD_ID=2017-03-31-0215
PRETTY_NAME="Container Linux by CoreOS 1298.7.0 (Ladybug)"
ANSI_COLOR="38;5;75"
HOME_URL="https://coreos.com/"
BUG_REPORT_URL="https://github.com/coreos/bugs/issues

Environment

HP gen9 server

Bug Description

I'm using CoreOS matchbox for network boot and provisioning my private cloud.
matchbox uses systemd units for booting the system and I'm following matchbod examples at https://github.com/coreos/matchbox/blob/v0.6.0/examples/ignition/install-reboot.yaml

installer.service contains Requires=network-online.target and After=network-online.target but the service fails to curl the ignition file needed for installer and returns 7/failed_to_connect error, but when I curl the file manually after boot time, the curl is successful

[crawford]

The underlying issue is that network-online.target isn't a silver bullet for detecting if the network is up. It's intended to be used with legacy applications that don't handle network changes properly. This example should be smart enough to retry the network operation and therefore drop the network online dependency.

[MohammadKarimi23]

I actually solved the problem using until ping command as 'ExecStartPre' like below

[Service]
        ExecStartPre=/bin/sh -c 'until ping -c1 google.com; do sleep 1; done;'
        ExecStartPre=/usr/bin/mkdir -p /etc/kubernetes/ssl
        ExecStart=/usr/bin/bash -c "[ -f /etc/kubernetes/ssl/%i ] ||  curl {{.k8s_cert_endpoint}}/tls/%i -o /etc/kubernetes/ssl/%i"

but I appreciate if you show me a way to do that using systemd units

[crawford]

That seems like a fine solution to me.

[euank]

I opened poseidon/matchbox#596 to hopefully fix this. I think discussion can be moved there.