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changing dnsmasq pre start script #2

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mjudeikis merged 1 commit into from
Jul 1, 2021
Merged

changing dnsmasq pre start script #2

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110 changes: 109 additions & 1 deletion pkg/aro/dnsmasq/dnsmasq.go
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Original file line number Diff line number Diff line change
Expand Up @@ -40,7 +40,7 @@ Before=bootkube.service
# This file is a product of user DNS settings on the VNET. We will replace this file to point to
# dnsmasq instance on the node. dnsmasq will inject certain dns records we need and forward rest of the queries to
# resolv.conf.dnsmasq upstream customer dns.
ExecStartPre=/bin/bash -c 'if /usr/bin/test -f "/etc/resolv.conf.dnsmasq"; then echo "already replaced resolv.conf.dnsmasq"; else /bin/cp /etc/resolv.conf /etc/resolv.conf.dnsmasq; fi; /bin/sed -ni -e "/^nameserver /!p; \\$$a nameserver $$(ip -f inet -o addr show eth0|cut -d\ -f 7 | cut -d/ -f 1)" /etc/resolv.conf; /usr/sbin/restorecon /etc/resolv.conf'
ExecStartPre=/bin/bash /usr/local/bin/aro-dnsmasq-pre.sh
ExecStart=/usr/sbin/dnsmasq -k
ExecStopPost=/bin/bash -c '/bin/mv /etc/resolv.conf.dnsmasq /etc/resolv.conf; /usr/sbin/restorecon /etc/resolv.conf'
Restart=always
Expand All @@ -49,6 +49,62 @@ Restart=always
WantedBy=multi-user.target
{{ end }}

{{ define "aro-dnsmasq-pre.sh" }}
#!/bin/bash
set -euo pipefail

# This bash script is a part of the ARO DnsMasq configuration
# It's deployed as part of the 99-aro-dns-* machine config
# See https://github.com/Azure/ARO-RP

# This file can be rerun and the effect is idempotent, output might change if the DHCP configuration changes

TMPSELFRESOLV=$(mktemp)
TMPNETRESOLV=$(mktemp)

echo "# Generated for dnsmasq.service - should point to self" > $TMPSELFRESOLV
echo "# Generated for dnsmasq.service - should contain DHCP configured DNS" > $TMPNETRESOLV

if nmcli device show br-ex; then
echo "OVN mode - br-ex device exists"
#getting DNS search strings
SEARCH_RAW=$(nmcli --get IP4.DOMAIN device show br-ex)
#getting DNS servers
NAMESERVER_RAW=$(nmcli --get IP4.DNS device show br-ex)
LOCAL_IPS_RAW=$(nmcli --get IP4.ADDRESS device show br-ex)
else
NETDEV=$(nmcli --get device connection show --active | head -n 1) #there should be only one active device
echo "OVS SDN mode - br-ex not found, using device $NETDEV"
SEARCH_RAW=$(nmcli --get IP4.DOMAIN device show $NETDEV)
NAMESERVER_RAW=$(nmcli --get IP4.DNS device show $NETDEV)
LOCAL_IPS_RAW=$(nmcli --get IP4.ADDRESS device show $NETDEV)
fi

#search line
echo "search $SEARCH_RAW" | tr '\n' ' ' >> $TMPNETRESOLV
echo "" >> $TMPNETRESOLV
echo "search $SEARCH_RAW" | tr '\n' ' ' >> $TMPSELFRESOLV
echo "" >> $TMPSELFRESOLV

#nameservers as separate lines
echo "$NAMESERVER_RAW" | while read -r line
do
echo "nameserver $line" >> $TMPNETRESOLV
done
# device IPs are returned in address/mask format
echo "$LOCAL_IPS_RAW" | while read -r line
do
echo "nameserver $line" | cut -d'/' -f 1 >> $TMPSELFRESOLV
done

# done, copying files to destination locations and cleaning up
/bin/cp $TMPNETRESOLV /etc/resolv.conf.dnsmasq
chmod 0744 /etc/resolv.conf.dnsmasq
/bin/cp $TMPSELFRESOLV /etc/resolv.conf
/usr/sbin/restorecon /etc/resolv.conf
/bin/rm $TMPNETRESOLV
/bin/rm $TMPSELFRESOLV
{{ end }}
`))

func config(clusterDomain, apiIntIP, ingressIP string) ([]byte, error) {
Expand Down Expand Up @@ -81,6 +137,17 @@ func service() (string, error) {
return buf.String(), nil
}

func startpre() ([]byte, error) {
buf := &bytes.Buffer{}

err := t.ExecuteTemplate(buf, "aro-dnsmasq-pre.sh", nil)
if err != nil {
return nil, err
}

return buf.Bytes(), nil
}

func Ignition2Config(clusterDomain, apiIntIP, ingressIP string) (*ign2types.Config, error) {
service, err := service()
if err != nil {
Expand All @@ -92,6 +159,11 @@ func Ignition2Config(clusterDomain, apiIntIP, ingressIP string) (*ign2types.Conf
return nil, err
}

startpre, err := startpre()
if err != nil {
return nil, err
}

return &ign2types.Config{
Ignition: ign2types.Ignition{
Version: ign2types.MaxVersion.String(),
Expand All @@ -114,6 +186,22 @@ func Ignition2Config(clusterDomain, apiIntIP, ingressIP string) (*ign2types.Conf
Mode: ignutil.IntToPtr(0644),
},
},
{
Node: ign2types.Node{
Filesystem: "root",
Overwrite: ignutil.BoolToPtr(true),
Path: "/usr/local/bin/aro-dnsmasq-pre.sh",
User: &ign2types.NodeUser{
Name: "root",
},
},
FileEmbedded1: ign2types.FileEmbedded1{
Contents: ign2types.FileContents{
Source: dataurl.EncodeBytes(startpre),
},
Mode: ignutil.IntToPtr(0744),
},
},
},
},
Systemd: ign2types.Systemd{
Expand All @@ -139,6 +227,11 @@ func Ignition3Config(clusterDomain, apiIntIP, ingressIP string) (*ign3types.Conf
return nil, err
}

startpre, err := startpre()
if err != nil {
return nil, err
}

return &ign3types.Config{
Ignition: ign3types.Ignition{
Version: ign3types.MaxVersion.String(),
Expand All @@ -160,6 +253,21 @@ func Ignition3Config(clusterDomain, apiIntIP, ingressIP string) (*ign3types.Conf
Mode: ignutil.IntToPtr(0644),
},
},
{
Node: ign3types.Node{
Overwrite: ignutil.BoolToPtr(true),
Path: "/usr/local/bin/aro-dnsmasq-pre.sh",
User: ign3types.NodeUser{
Name: ignutil.StrToPtr("root"),
},
},
FileEmbedded1: ign3types.FileEmbedded1{
Contents: ign3types.Resource{
Source: ignutil.StrToPtr(dataurl.EncodeBytes(startpre)),
},
Mode: ignutil.IntToPtr(0744),
},
},
},
},
Systemd: ign3types.Systemd{
Expand Down