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Do not accept DHCP DNS servers if manually defined. Check resolv.conf…
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… file for updated --dns-server instead of guestinfo. (#7824)

* Enable SSH and check /etc/resolv.conf directly for the appropriate config changes.
* DNS vic-machine test has been updated to look for the real data.
* Removed guest info check.
* Improved behavior with DHCP DNS server assignment. Ignore DHCP settings if DNS servers are set manually via --dns-server option.
* Added more logs to track which DHCP options are set.
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@vburenin
vburenin authored Apr 27, 2018
1 parent 26ee2f9 commit 5b15145
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Showing 2 changed files with 45 additions and 18 deletions.
16 changes: 13 additions & 3 deletions lib/tether/ops_linux.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -374,9 +374,11 @@ func getDynamicIP(t Netlink, link netlink.Link, endpoint *NetworkEndpoint) (clie

params := []byte{byte(dhcp4.OptionSubnetMask)}
if ip.IsUnspecifiedIP(endpoint.Network.Gateway.IP) {
log.Debugf("No gateway IP. Asking DHCP.")
params = append(params, byte(dhcp4.OptionRouter))
}
if len(endpoint.Network.Nameservers) == 0 {
log.Debugf("No name servers configured. Asking DHCP.")
params = append(params, byte(dhcp4.OptionDomainNameServer))
}

Expand Down Expand Up @@ -416,6 +418,8 @@ func updateEndpoint(newIP *net.IPNet, endpoint *NetworkEndpoint) {
return
}

log.Debugf("DHCP data: %#v", dhcp)
log.Debugf("DHCP DNS Servers %s: ", dhcp.Nameservers)
endpoint.Assigned = dhcp.Assigned
endpoint.Network.Assigned.Gateway = dhcp.Gateway
if len(dhcp.Nameservers) > 0 {
Expand Down Expand Up @@ -582,11 +586,15 @@ func (t *BaseOperations) updateHosts(endpoint *NetworkEndpoint) error {
func (t *BaseOperations) updateNameservers(endpoint *NetworkEndpoint) error {
gw := endpoint.Network.Assigned.Gateway
ns := endpoint.Network.Assigned.Nameservers
// if `--dns-server` option is supplied at VCH creation, do not overwrite with
// dhcp-provided name servers, and make sure they appear at the top of the list

if len(ns) > 0 && len(endpoint.Network.Nameservers) > 0 {
log.Debugf("DHCP server returned DNS server configuration, it will be ignored")
}
// Manually set DNS servers should always be DNS servers that are being in use.
if len(endpoint.Network.Nameservers) > 0 {
ns = append(endpoint.Network.Nameservers, ns...)
ns = endpoint.Network.Nameservers
}

// Add nameservers
// This is incredibly trivial for now - should be updated to a less messy approach
if len(ns) > 0 {
Expand Down Expand Up @@ -616,6 +624,8 @@ func ApplyEndpoint(nl Netlink, t *BaseOperations, endpoint *NetworkEndpoint) err
return nil // already applied
}

log.Debugf("Static name servers: %s", endpoint.Network.Nameservers)

// Locate interface
slot, err := strconv.Atoi(endpoint.ID)
if err != nil {
Expand Down
47 changes: 32 additions & 15 deletions tests/test-cases/Group6-VIC-Machine/6-16-Config.robot
View file
Original file line number Diff line number Diff line change
Expand Up @@ -179,21 +179,38 @@ Configure VCH https-proxy through vch id
Should Not Contain ${output} proxy.vmware.com:3128

Configure VCH DNS server
${status}= Get State Of Github Issue 7775
Run Keyword If '${status}' == 'closed' Fail Test 6-16-Config.robot needs to be updated now that Issue #7775 has been resolved
Log Issue \#7775 is blocking implementation WARN
# ${output}= Run bin/vic-machine-linux inspect config --name=%{VCH-NAME} --target=%{TEST_URL} --thumbprint=%{TEST_THUMBPRINT} --user=%{TEST_USERNAME} --password=%{TEST_PASSWORD} --timeout %{TEST_TIMEOUT}
# Should Not Contain ${output} --dns-server
# ${output}= Run bin/vic-machine-linux configure --name=%{VCH-NAME} --target=%{TEST_URL} --thumbprint=%{TEST_THUMBPRINT} --user=%{TEST_USERNAME} --password=%{TEST_PASSWORD} --timeout %{TEST_TIMEOUT} --dns-server 10.118.81.1 --dns-server 10.118.81.2
# Should Contain ${output} Completed successfully
# ${output}= Run bin/vic-machine-linux inspect config --name=%{VCH-NAME} --target=%{TEST_URL} --thumbprint=%{TEST_THUMBPRINT} --user=%{TEST_USERNAME} --password=%{TEST_PASSWORD} --timeout %{TEST_TIMEOUT}
# Should Contain ${output} --dns-server=10.118.81.1
# Should Contain ${output} --dns-server=10.118.81.2
# Wait Until Keyword Succeeds 10x 6s Wait For DNS Update ${true}
# ${output}= Run bin/vic-machine-linux configure --name=%{VCH-NAME} --target=%{TEST_URL} --thumbprint=%{TEST_THUMBPRINT} --user=%{TEST_USERNAME} --password=%{TEST_PASSWORD} --timeout %{TEST_TIMEOUT} --dns-server ""
# Should Contain ${output} Completed successfully
# Should Not Contain ${output} --dns-server
# Wait Until Keyword Succeeds 10x 6s Wait For DNS Update ${false}
${output}= Run bin/vic-machine-linux inspect config --name=%{VCH-NAME} --target=%{TEST_URL} --thumbprint=%{TEST_THUMBPRINT} --user=%{TEST_USERNAME} --password=%{TEST_PASSWORD} --timeout %{TEST_TIMEOUT}
Should Not Contain ${output} --dns-server
${output}= Run bin/vic-machine-linux configure --name=%{VCH-NAME} --target=%{TEST_URL} --thumbprint=%{TEST_THUMBPRINT} --user=%{TEST_USERNAME} --password=%{TEST_PASSWORD} --timeout %{TEST_TIMEOUT} --dns-server 10.118.81.1 --dns-server 10.118.81.2
Should Contain ${output} Completed successfully

Enable VCH SSH
${rc} ${output}= Run And Return Rc and Output sshpass -p %{TEST_PASSWORD} ssh -o StrictHostKeyChecking=no root@%{VCH-IP} cat /etc/resolv.conf
Should Be Equal As Integers ${rc} 0
Should Contain ${output} nameserver 10.118.81.1
Should Contain ${output} nameserver 10.118.81.2

${rc} ${output}= Run And Return Rc and Output sshpass -p %{TEST_PASSWORD} ssh -o StrictHostKeyChecking=no root@%{VCH-IP} cat /etc/resolv.conf | grep nameserver | wc -l
Should Be Equal As Integers ${rc} 0
Should Contain ${output} 2

${output}= Run bin/vic-machine-linux inspect config --name=%{VCH-NAME} --target=%{TEST_URL} --thumbprint=%{TEST_THUMBPRINT} --user=%{TEST_USERNAME} --password=%{TEST_PASSWORD} --timeout %{TEST_TIMEOUT}
Should Contain ${output} --dns-server=10.118.81.1
Should Contain ${output} --dns-server=10.118.81.2

${output}= Run bin/vic-machine-linux configure --name=%{VCH-NAME} --target=%{TEST_URL} --thumbprint=%{TEST_THUMBPRINT} --user=%{TEST_USERNAME} --password=%{TEST_PASSWORD} --timeout %{TEST_TIMEOUT} --dns-server ""
Should Contain ${output} Completed successfully
Should Not Contain ${output} --dns-server

# Remove old SSH key since it changes after reboot.
${rc}= Run And Return Rc ssh-keygen -f "/root/.ssh/known_hosts" -R %{VCH-IP}
Should Be Equal As Integers ${rc} 0

Enable VCH SSH
${rc} ${output}= Run And Return Rc and Output sshpass -p %{TEST_PASSWORD} ssh -o StrictHostKeyChecking=no root@%{VCH-IP} cat /etc/resolv.conf
Should Be Equal As Integers ${rc} 0
Should Not Contain ${output} nameserver 10.118.81.1
Should Not Contain ${output} nameserver 10.118.81.2

Configure VCH resources
${output}= Run bin/vic-machine-linux configure --name=%{VCH-NAME} --target=%{TEST_URL}%{TEST_DATACENTER} --thumbprint=%{TEST_THUMBPRINT} --user=%{TEST_USERNAME} --password=%{TEST_PASSWORD} --timeout %{TEST_TIMEOUT} --cpu 5129 --cpu-reservation 10 --cpu-shares 8000 --memory 4096 --memory-reservation 10 --memory-shares 163840
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