feat: support localdns hosts plugin refresh override by saewoni · Pull Request #8895 · Azure/AgentBaker

saewoni · 2026-07-11T00:12:27Z

What this PR does / why we need it:

This change lets AgentBaker carry a LocalDNS hosts plugin refresh interval from node bootstrapping config down to provisioning, instead of relying on the hardcoded 15 minute timer cadence.

It adds the new LocalDNS field to the datamodel and aks-node-controller proto/parser paths, emits the value into both legacy CSE and scriptless env, and updates cse_config.sh to rewrite aks-localdns-hosts-setup.timer when a positive interval is provided. When the field is unset or invalid, provisioning keeps the existing default behavior.

This complements the corresponding AKS-RP change in PR 16401188.

Validation run:

make validate-shell
docker run --rm -v /home/sakwa/AgentBaker:/workspace -w /workspace shellspec-docker --shell bash --format d spec/parts/linux/cloud-init/artifacts/cse_config_spec.sh
go test ./pkg/agent/...
cd aks-node-controller && go test ./parser
./hack/tools/bin/golangci-lint run ./pkg/agent/...
cd aks-node-controller && ../hack/tools/bin/golangci-lint run ./parser/...

Which issue(s) this PR fixes:

Fixes #

github-actions · 2026-07-11T00:12:59Z

The latest Buf updates on your PR. Results from workflow Buf CI / buf (pull_request).

Build	Format	Lint	Breaking	Updated (UTC)
`✅ passed`	`✅ passed`	`✅ passed`	`✅ passed`	Jul 13, 2026, 6:08 PM

Copilot

Pull request overview

This PR adds support for configuring the AKS LocalDNS hosts plugin refresh interval end-to-end (datamodel → template/provisioning env → CSE behavior), replacing reliance on the fixed 15-minute systemd timer cadence when an explicit positive interval is provided.

Changes:

Extend the AgentBaker datamodel and template func map to carry hostsPluginRefreshIntervalInSeconds into provisioning.
Extend aks-node-controller proto + parser to emit LOCALDNS_HOSTS_PLUGIN_REFRESH_INTERVAL_IN_SECONDS for scriptless provisioning.
Update Linux CSE (cse_config.sh) to rewrite aks-localdns-hosts-setup.timer OnUnitActiveSec when a valid positive interval is provided, with new/updated tests.

Reviewed changes

Copilot reviewed 11 out of 12 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
spec/parts/linux/cloud-init/artifacts/cse_config_spec.sh	Adds ShellSpec coverage for timer interval override behavior.
pkg/agent/datamodel/types.go	Adds `HostsPluginRefreshIntervalInSeconds` to `LocalDNSProfile` JSON schema.
pkg/agent/baker.go	Adds template function to render refresh interval into CSE templates.
pkg/agent/baker_test.go	Unit tests for the new template function behavior (nil/invalid/valid).
parts/linux/cloud-init/artifacts/cse_config.sh	Applies the provided interval by editing the systemd timer before enabling it.
parts/linux/cloud-init/artifacts/cse_cmd.sh	Emits the new refresh interval env var for legacy CSE flow.
aks-node-controller/proto/aksnodeconfig/v1/localdns_config.proto	Adds optional refresh interval field to LocalDNS proto.
aks-node-controller/pkg/gen/aksnodeconfig/v1/localdns_config.pb.go	Regenerates protobuf bindings for the new field.
aks-node-controller/parser/parser.go	Exposes the new interval as a CSE env var in scriptless mode.
aks-node-controller/parser/parser_test.go	Validates env var emission in integration-style parser tests.
aks-node-controller/parser/helper.go	Adds helper to stringify/validate refresh interval from proto config.
aks-node-controller/parser/helper_test.go	Unit tests for the new helper’s nil/invalid/valid cases.

Files not reviewed (1)

aks-node-controller/pkg/gen/aksnodeconfig/v1/localdns_config.pb.go: Generated file

Copilot

Pull request overview

Copilot reviewed 11 out of 12 changed files in this pull request and generated no new comments.

Files not reviewed (1)

aks-node-controller/pkg/gen/aksnodeconfig/v1/localdns_config.pb.go: Generated file

awesomenix · 2026-07-12T15:56:17Z

+                ;;
+            *)
+                if [ "${hosts_plugin_refresh_interval}" -gt 0 ]; then
+                    sed -i "s/^OnUnitActiveSec=.*/OnUnitActiveSec=${hosts_plugin_refresh_interval}s/" "${hosts_setup_timer}"


Seems very hacky. I would think that there would be some form of timer.template and then you render it either on agentbaker side or aks-node-controller side?

Addressed in commit 8366dcd.

Instead of rewriting the shipped timer unit in place, the refresh override now uses a systemd drop-in:

AgentBaker/parts/linux/cloud-init/artifacts/cse_config.sh

Lines 1824 to 1848 in 8366dcd

local hosts_plugin_refresh_interval="${LOCALDNS_HOSTS_PLUGIN_REFRESH_INTERVAL_IN_SECONDS:-}"

local hosts_setup_timer_override="${hosts_setup_timer}.d/10-refresh-interval.conf"

local min_hosts_plugin_refresh_interval_in_seconds=5

if [ -z "${hosts_plugin_refresh_interval}" ]; then

removeAKSLocalDNSHostsSetupTimerOverride "${hosts_setup_timer_override}"

else

local should_override_refresh_interval="false"

case "${hosts_plugin_refresh_interval}" in

*[!0-9]*)

;;

*)

if [ "${hosts_plugin_refresh_interval}" -ge "${min_hosts_plugin_refresh_interval_in_seconds}" ]; then

should_override_refresh_interval="true"

fi

;;

esac

if [ "${should_override_refresh_interval}" = "true" ]; then

mkdir -p "$(dirname "${hosts_setup_timer_override}")"

cat > "${hosts_setup_timer_override}" <<EOF

[Timer]

OnUnitActiveSec=${hosts_plugin_refresh_interval}s

AccuracySec=1s

EOF

The base timer file stays generic/default-only here:

AgentBaker/parts/linux/cloud-init/artifacts/aks-localdns-hosts-setup.timer

Lines 7 to 13 in 8366dcd

# Default refresh cadence. Provisioning may override this with a systemd drop-in

# when LOCALDNS_HOSTS_PLUGIN_REFRESH_INTERVAL_IN_SECONDS is set. 15 minutes

# balances freshness against unnecessary DNS traffic — stale IPs would cause the

# hosts plugin to serve unreachable addresses until the next refresh.

OnUnitActiveSec=15min

# Default timer accuracy. Provisioning may lower this for shorter cadences.

AccuracySec=1min

yewmsft

nice, right direction — configurable over the hardcoded 15min, additive optional field, empty preserves default. one blocking thing (AccuracySec, else sub-minute intervals silently don't fire) + a few asks inline.

yewmsft · 2026-07-12T18:55:23Z

+                ;;
+            *)
+                if [ "${hosts_plugin_refresh_interval}" -gt 0 ]; then
+                    sed -i "s/^OnUnitActiveSec=.*/OnUnitActiveSec=${hosts_plugin_refresh_interval}s/" "${hosts_setup_timer}"


this only rewrites OnUnitActiveSec, but the shipped aks-localdns-hosts-setup.timer also has AccuracySec=1min. systemd won't fire more accurately than the accuracy window, so OnUnitActiveSec=5s gets coalesced to ~1min — sub-minute cadence won't actually happen. RP (16401188) is passing seconds, so this silently won't deliver. need to drop AccuracySec too:

sed -i "s/^AccuracySec=.*/AccuracySec=1s/" "${hosts_setup_timer}"

did you verify on a real node that a small value actually fires at that cadence? i don't think it does as-is.

Addressed in commit 8366dcd.

The override now uses a systemd drop-in and sets both OnUnitActiveSec and AccuracySec=1s here:

AgentBaker/parts/linux/cloud-init/artifacts/cse_config.sh

Lines 1824 to 1848 in 8366dcd

local hosts_plugin_refresh_interval="${LOCALDNS_HOSTS_PLUGIN_REFRESH_INTERVAL_IN_SECONDS:-}"

local hosts_setup_timer_override="${hosts_setup_timer}.d/10-refresh-interval.conf"

local min_hosts_plugin_refresh_interval_in_seconds=5

if [ -z "${hosts_plugin_refresh_interval}" ]; then

removeAKSLocalDNSHostsSetupTimerOverride "${hosts_setup_timer_override}"

else

local should_override_refresh_interval="false"

case "${hosts_plugin_refresh_interval}" in

*[!0-9]*)

;;

*)

if [ "${hosts_plugin_refresh_interval}" -ge "${min_hosts_plugin_refresh_interval_in_seconds}" ]; then

should_override_refresh_interval="true"

fi

;;

esac

if [ "${should_override_refresh_interval}" = "true" ]; then

mkdir -p "$(dirname "${hosts_setup_timer_override}")"

cat > "${hosts_setup_timer_override}" <<EOF

[Timer]

OnUnitActiveSec=${hosts_plugin_refresh_interval}s

AccuracySec=1s

EOF

ShellSpec coverage for the generated override is here:

AgentBaker/spec/parts/linux/cloud-init/artifacts/cse_config_spec.sh

Lines 1507 to 1515 in 8366dcd

It 'should update the timer refresh interval when provided'

LOCALDNS_HOSTS_PLUGIN_REFRESH_INTERVAL_IN_SECONDS="30"

When call enableAKSLocalDNSHostsSetup

The status should be success

The output should include "Configured aks-localdns-hosts-setup timer refresh interval to 30s."

The output should include "systemctl daemon-reload"

The contents of file "${AKS_LOCALDNS_HOSTS_SETUP_TIMER}.d/10-refresh-interval.conf" should include "OnUnitActiveSec=30s"

The contents of file "${AKS_LOCALDNS_HOSTS_SETUP_TIMER}.d/10-refresh-interval.conf" should include "AccuracySec=1s"

The contents of file "$AKS_LOCALDNS_HOSTS_SETUP_TIMER" should include "OnUnitActiveSec=15min"

I did not run a live-node cadence check in this branch; the validation here was ShellSpec/shellcheck rather than a real node.

yewmsft · 2026-07-12T18:55:23Z

+                echo "Warning: LOCALDNS_HOSTS_PLUGIN_REFRESH_INTERVAL_IN_SECONDS must be a positive integer, got '${hosts_plugin_refresh_interval}'. Using default timer interval."
+                ;;
+            *)
+                if [ "${hosts_plugin_refresh_interval}" -gt 0 ]; then


this is the only bound — RP validates >0, so 1 is legal and would hit live DNS every second on every localdns node. do we want a floor? at least call out a sane min.

Addressed in commit 8366dcd.

Added a 5s floor here:

AgentBaker/parts/linux/cloud-init/artifacts/cse_config.sh

Lines 1824 to 1862 in 8366dcd

local hosts_plugin_refresh_interval="${LOCALDNS_HOSTS_PLUGIN_REFRESH_INTERVAL_IN_SECONDS:-}"

local hosts_setup_timer_override="${hosts_setup_timer}.d/10-refresh-interval.conf"

local min_hosts_plugin_refresh_interval_in_seconds=5

if [ -z "${hosts_plugin_refresh_interval}" ]; then

removeAKSLocalDNSHostsSetupTimerOverride "${hosts_setup_timer_override}"

else

local should_override_refresh_interval="false"

case "${hosts_plugin_refresh_interval}" in

*[!0-9]*)

;;

*)

if [ "${hosts_plugin_refresh_interval}" -ge "${min_hosts_plugin_refresh_interval_in_seconds}" ]; then

should_override_refresh_interval="true"

fi

;;

esac

if [ "${should_override_refresh_interval}" = "true" ]; then

mkdir -p "$(dirname "${hosts_setup_timer_override}")"

cat > "${hosts_setup_timer_override}" <<EOF

[Timer]

OnUnitActiveSec=${hosts_plugin_refresh_interval}s

AccuracySec=1s

EOF

chmod 0644 "${hosts_setup_timer_override}"

if grep -q "^OnUnitActiveSec=${hosts_plugin_refresh_interval}s$" "${hosts_setup_timer_override}" &&

grep -q "^AccuracySec=1s$" "${hosts_setup_timer_override}"; then

if systemctl daemon-reload; then

echo "Configured aks-localdns-hosts-setup timer refresh interval to ${hosts_plugin_refresh_interval}s."

else

echo "Warning: Failed to reload systemd after updating ${hosts_setup_timer_override}"

fi

else

echo "Warning: Failed to update ${hosts_setup_timer_override} with refresh interval ${hosts_plugin_refresh_interval}s"

fi

else

echo "Warning: LOCALDNS_HOSTS_PLUGIN_REFRESH_INTERVAL_IN_SECONDS must be an integer >= ${min_hosts_plugin_refresh_interval_in_seconds}, got '${hosts_plugin_refresh_interval}'. Using default timer interval."

removeAKSLocalDNSHostsSetupTimerOverride "${hosts_setup_timer_override}"

yewmsft · 2026-07-12T18:55:23Z

+// getLocalDnsHostsPluginRefreshIntervalInSeconds returns the refresh interval in seconds
+// for the LocalDNS hosts plugin timer. Empty string means use the default timer cadence.
+func getLocalDnsHostsPluginRefreshIntervalInSeconds(config *aksnodeconfigv1.Configuration) string {
+	if config == nil || config.GetLocalDnsProfile() == nil {


GetLocalDnsProfile() and GetHostsPluginRefreshIntervalInSeconds() are nil-safe on nil receivers. drop this guard and just call the getters:

refresh := config.GetLocalDnsProfile().GetHostsPluginRefreshIntervalInSeconds() if refresh <= 0 { return "" }

(baker.go is a plain datamodel struct, not proto — keep the nil checks there.)

Addressed in commit 8366dcd.

Dropped the explicit nil guard and now rely on the proto getters nil-safe behavior here:

AgentBaker/aks-node-controller/parser/helper.go

Lines 892 to 899 in 8366dcd

// getLocalDnsHostsPluginRefreshIntervalInSeconds returns the refresh interval in seconds

// for the LocalDNS hosts plugin timer. Empty string means use the default timer cadence.

func getLocalDnsHostsPluginRefreshIntervalInSeconds(config *aksnodeconfigv1.Configuration) string {

refreshIntervalInSeconds := config.GetLocalDnsProfile().GetHostsPluginRefreshIntervalInSeconds()

if refreshIntervalInSeconds <= 0 {

return ""

}

return strconv.FormatInt(int64(refreshIntervalInSeconds), 10)

yewmsft · 2026-07-12T18:55:23Z

            The output should include "systemctlEnableAndStartNoBlock aks-localdns-hosts-setup.timer 30"
        End

+        It 'should update the timer refresh interval when provided'


only the happy path is covered. the *[!0-9]* warning branch and the empty/0 -> default-preserved path never run in test. add a bad-format case (e.g. "abc") asserting the timer stays 15min, and an unset case. otherwise would this short circuit your failure code path?

Addressed in commit 8366dcd.

Added coverage for the provided interval, unset/default-restore, invalid-format/default-preserved, and below-min/default-preserved cases here:

AgentBaker/spec/parts/linux/cloud-init/artifacts/cse_config_spec.sh

Lines 1507 to 1545 in 8366dcd

It 'should update the timer refresh interval when provided'

LOCALDNS_HOSTS_PLUGIN_REFRESH_INTERVAL_IN_SECONDS="30"

When call enableAKSLocalDNSHostsSetup

The status should be success

The output should include "Configured aks-localdns-hosts-setup timer refresh interval to 30s."

The output should include "systemctl daemon-reload"

The contents of file "${AKS_LOCALDNS_HOSTS_SETUP_TIMER}.d/10-refresh-interval.conf" should include "OnUnitActiveSec=30s"

The contents of file "${AKS_LOCALDNS_HOSTS_SETUP_TIMER}.d/10-refresh-interval.conf" should include "AccuracySec=1s"

The contents of file "$AKS_LOCALDNS_HOSTS_SETUP_TIMER" should include "OnUnitActiveSec=15min"

End

It 'should restore the default timer when refresh interval is unset'

mkdir -p "${AKS_LOCALDNS_HOSTS_SETUP_TIMER}.d"

cat > "${AKS_LOCALDNS_HOSTS_SETUP_TIMER}.d/10-refresh-interval.conf" <<'OVERRIDE_EOF'

[Timer]

OnUnitActiveSec=30s

AccuracySec=1s

OVERRIDE_EOF

When call enableAKSLocalDNSHostsSetup

The status should be success

The output should include "Restored default aks-localdns-hosts-setup timer refresh interval."

The output should include "systemctl daemon-reload"

The contents of file "$AKS_LOCALDNS_HOSTS_SETUP_TIMER" should include "OnUnitActiveSec=15min"

The file "${AKS_LOCALDNS_HOSTS_SETUP_TIMER}.d/10-refresh-interval.conf" should not be exist

End

It 'should keep the default timer when refresh interval is invalid'

LOCALDNS_HOSTS_PLUGIN_REFRESH_INTERVAL_IN_SECONDS="abc"

When call enableAKSLocalDNSHostsSetup

The status should be success

The output should include "must be an integer >= 5, got 'abc'. Using default timer interval."

The contents of file "$AKS_LOCALDNS_HOSTS_SETUP_TIMER" should include "OnUnitActiveSec=15min"

The file "${AKS_LOCALDNS_HOSTS_SETUP_TIMER}.d/10-refresh-interval.conf" should not be exist

End

It 'should keep the default timer when refresh interval is below minimum'

LOCALDNS_HOSTS_PLUGIN_REFRESH_INTERVAL_IN_SECONDS="1"

When call enableAKSLocalDNSHostsSetup

The status should be success

yewmsft · 2026-07-12T18:55:23Z

 LOCALDNS_COREFILE_WITH_HOSTS=${LOCALDNS_COREFILE_WITH_HOSTS:-}
 SHOULD_ENABLE_HOSTS_PLUGIN=${SHOULD_ENABLE_HOSTS_PLUGIN:-false}
 LOCALDNS_CRITICAL_FQDNS=${LOCALDNS_CRITICAL_FQDNS:-}
+LOCALDNS_HOSTS_PLUGIN_REFRESH_INTERVAL_IN_SECONDS=${LOCALDNS_HOSTS_PLUGIN_REFRESH_INTERVAL_IN_SECONDS:-}


who reads this? the interval only drives the timer rewrite at provision time — the periodic aks-localdns-hosts-setup service doesn't consume it. same for the write at L1799. if nobody reads them, drop both.

Addressed in commit 8366dcd.

The interval is no longer written into either localdns environment file. The generated localdns env now stops at LOCALDNS_CRITICAL_FQDNS here:

AgentBaker/parts/linux/cloud-init/artifacts/cse_config.sh

Lines 1647 to 1653 in 8366dcd

cat > "${LOCALDNS_ENV_FILE}" <<EOF

LOCALDNS_BASE64_ENCODED_COREFILE=${corefile_base}

LOCALDNS_COREFILE_BASE=${corefile_base}

LOCALDNS_COREFILE_WITH_HOSTS=${LOCALDNS_COREFILE_WITH_HOSTS:-}

SHOULD_ENABLE_HOSTS_PLUGIN=${SHOULD_ENABLE_HOSTS_PLUGIN:-false}

LOCALDNS_CRITICAL_FQDNS=${LOCALDNS_CRITICAL_FQDNS:-}

EOF

And the minimal hosts-setup env write is only:

AgentBaker/parts/linux/cloud-init/artifacts/cse_config.sh

Lines 1808 to 1815 in 8366dcd

# Write a minimal environment file so the systemd service (which reads from

# /etc/localdns/environment via EnvironmentFile=) has LOCALDNS_CRITICAL_FQDNS available.

# generateLocalDNSFiles() overwrites this later with the full content including corefiles.

local env_file="/etc/localdns/environment"

mkdir -p "$(dirname "${env_file}")"

cat > "${env_file}" <<EOF

LOCALDNS_CRITICAL_FQDNS=${LOCALDNS_CRITICAL_FQDNS}

EOF

The interval is only consumed at provisioning time for the timer drop-in here:

AgentBaker/parts/linux/cloud-init/artifacts/cse_config.sh

Lines 1824 to 1848 in 8366dcd

local hosts_plugin_refresh_interval="${LOCALDNS_HOSTS_PLUGIN_REFRESH_INTERVAL_IN_SECONDS:-}"

local hosts_setup_timer_override="${hosts_setup_timer}.d/10-refresh-interval.conf"

local min_hosts_plugin_refresh_interval_in_seconds=5

if [ -z "${hosts_plugin_refresh_interval}" ]; then

removeAKSLocalDNSHostsSetupTimerOverride "${hosts_setup_timer_override}"

else

local should_override_refresh_interval="false"

case "${hosts_plugin_refresh_interval}" in

*[!0-9]*)

;;

*)

if [ "${hosts_plugin_refresh_interval}" -ge "${min_hosts_plugin_refresh_interval_in_seconds}" ]; then

should_override_refresh_interval="true"

fi

;;

esac

if [ "${should_override_refresh_interval}" = "true" ]; then

mkdir -p "$(dirname "${hosts_setup_timer_override}")"

cat > "${hosts_setup_timer_override}" <<EOF

[Timer]

OnUnitActiveSec=${hosts_plugin_refresh_interval}s

AccuracySec=1s

EOF

yewmsft · 2026-07-12T18:55:23Z

+    local hosts_plugin_refresh_interval="${LOCALDNS_HOSTS_PLUGIN_REFRESH_INTERVAL_IN_SECONDS:-}"
+    if [ -n "${hosts_plugin_refresh_interval}" ]; then
+        case "${hosts_plugin_refresh_interval}" in
+            *[!0-9]*)


nit: this warning and the -gt 0 else below print the same message — collapse. also the "Refresh every 15 minutes..." comment in aks-localdns-hosts-setup.timer goes stale once you sed the value; make it generic.

Addressed in commit 8366dcd.

The warning is collapsed to the single default-preserving branch here:

AgentBaker/parts/linux/cloud-init/artifacts/cse_config.sh

Lines 1860 to 1862 in 8366dcd

else

echo "Warning: LOCALDNS_HOSTS_PLUGIN_REFRESH_INTERVAL_IN_SECONDS must be an integer >= ${min_hosts_plugin_refresh_interval_in_seconds}, got '${hosts_plugin_refresh_interval}'. Using default timer interval."

removeAKSLocalDNSHostsSetupTimerOverride "${hosts_setup_timer_override}"

And the shipped timer comments are generic/default-only here:

AgentBaker/parts/linux/cloud-init/artifacts/aks-localdns-hosts-setup.timer

Lines 7 to 13 in 8366dcd

# Default refresh cadence. Provisioning may override this with a systemd drop-in

# when LOCALDNS_HOSTS_PLUGIN_REFRESH_INTERVAL_IN_SECONDS is set. 15 minutes

# balances freshness against unnecessary DNS traffic — stale IPs would cause the

# hosts plugin to serve unreachable addresses until the next refresh.

OnUnitActiveSec=15min

# Default timer accuracy. Provisioning may lower this for shorter cadences.

AccuracySec=1min

Copilot

Pull request overview

Copilot reviewed 12 out of 13 changed files in this pull request and generated no new comments.

Files not reviewed (1)

aks-node-controller/pkg/gen/aksnodeconfig/v1/localdns_config.pb.go: Generated file

Copilot AI review requested due to automatic review settings July 11, 2026 00:12

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feat: support localdns hosts plugin refresh override

d03db7d

Copilot AI review requested due to automatic review settings July 11, 2026 06:53

saewoni force-pushed the sakwa/localdns-hosts-plugin-refresh-interval branch from 38e6e82 to d03db7d Compare July 11, 2026 06:53

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fix: address localdns timer review feedback

8366dcd

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	local hosts_plugin_refresh_interval="${LOCALDNS_HOSTS_PLUGIN_REFRESH_INTERVAL_IN_SECONDS:-}"
	local hosts_setup_timer_override="${hosts_setup_timer}.d/10-refresh-interval.conf"
	local min_hosts_plugin_refresh_interval_in_seconds=5

	if [ -z "${hosts_plugin_refresh_interval}" ]; then
	removeAKSLocalDNSHostsSetupTimerOverride "${hosts_setup_timer_override}"
	else
	local should_override_refresh_interval="false"
	case "${hosts_plugin_refresh_interval}" in
	[!0-9])
	;;
	*)
	if [ "${hosts_plugin_refresh_interval}" -ge "${min_hosts_plugin_refresh_interval_in_seconds}" ]; then
	should_override_refresh_interval="true"
	fi
	;;
	esac

	if [ "${should_override_refresh_interval}" = "true" ]; then
	mkdir -p "$(dirname "${hosts_setup_timer_override}")"
	cat > "${hosts_setup_timer_override}" <<EOF
	[Timer]
	OnUnitActiveSec=${hosts_plugin_refresh_interval}s
	AccuracySec=1s
	EOF

	# Default refresh cadence. Provisioning may override this with a systemd drop-in
	# when LOCALDNS_HOSTS_PLUGIN_REFRESH_INTERVAL_IN_SECONDS is set. 15 minutes
	# balances freshness against unnecessary DNS traffic — stale IPs would cause the
	# hosts plugin to serve unreachable addresses until the next refresh.
	OnUnitActiveSec=15min
	# Default timer accuracy. Provisioning may lower this for shorter cadences.
	AccuracySec=1min

	It 'should update the timer refresh interval when provided'
	LOCALDNS_HOSTS_PLUGIN_REFRESH_INTERVAL_IN_SECONDS="30"
	When call enableAKSLocalDNSHostsSetup
	The status should be success
	The output should include "Configured aks-localdns-hosts-setup timer refresh interval to 30s."
	The output should include "systemctl daemon-reload"
	The contents of file "${AKS_LOCALDNS_HOSTS_SETUP_TIMER}.d/10-refresh-interval.conf" should include "OnUnitActiveSec=30s"
	The contents of file "${AKS_LOCALDNS_HOSTS_SETUP_TIMER}.d/10-refresh-interval.conf" should include "AccuracySec=1s"
	The contents of file "$AKS_LOCALDNS_HOSTS_SETUP_TIMER" should include "OnUnitActiveSec=15min"

	// getLocalDnsHostsPluginRefreshIntervalInSeconds returns the refresh interval in seconds
	// for the LocalDNS hosts plugin timer. Empty string means use the default timer cadence.
	func getLocalDnsHostsPluginRefreshIntervalInSeconds(config *aksnodeconfigv1.Configuration) string {
	refreshIntervalInSeconds := config.GetLocalDnsProfile().GetHostsPluginRefreshIntervalInSeconds()
	if refreshIntervalInSeconds <= 0 {
	return ""
	}
	return strconv.FormatInt(int64(refreshIntervalInSeconds), 10)

	cat > "${LOCALDNS_ENV_FILE}" <<EOF
	LOCALDNS_BASE64_ENCODED_COREFILE=${corefile_base}
	LOCALDNS_COREFILE_BASE=${corefile_base}
	LOCALDNS_COREFILE_WITH_HOSTS=${LOCALDNS_COREFILE_WITH_HOSTS:-}
	SHOULD_ENABLE_HOSTS_PLUGIN=${SHOULD_ENABLE_HOSTS_PLUGIN:-false}
	LOCALDNS_CRITICAL_FQDNS=${LOCALDNS_CRITICAL_FQDNS:-}
	EOF

	# Write a minimal environment file so the systemd service (which reads from
	# /etc/localdns/environment via EnvironmentFile=) has LOCALDNS_CRITICAL_FQDNS available.
	# generateLocalDNSFiles() overwrites this later with the full content including corefiles.
	local env_file="/etc/localdns/environment"
	mkdir -p "$(dirname "${env_file}")"
	cat > "${env_file}" <<EOF
	LOCALDNS_CRITICAL_FQDNS=${LOCALDNS_CRITICAL_FQDNS}
	EOF

	else
	echo "Warning: LOCALDNS_HOSTS_PLUGIN_REFRESH_INTERVAL_IN_SECONDS must be an integer >= ${min_hosts_plugin_refresh_interval_in_seconds}, got '${hosts_plugin_refresh_interval}'. Using default timer interval."
	removeAKSLocalDNSHostsSetupTimerOverride "${hosts_setup_timer_override}"

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github-actions Bot commented Jul 11, 2026 •

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