Fix/dns hosts configuration

.github/workflows/sandbox-sanity-test.yml

@@ -296,63 +296,6 @@ jobs:
           sudo -E bash ./device-agent.sh k3s create-rsa-certs
           sudo -E bash ./device-agent.sh k3s create-ecdsa-certs
 
-      - name: Configure CoreDNS for k3s
-        run: |
-          RUNNER_IP=${RUNNER_IP}
-          echo "📡 Configuring CoreDNS with custom DNS entries..."
-
-          # Retry logic for ConfigMap update
-          for RETRY in {1..3}; do
-            echo "Attempt $RETRY to configure CoreDNS..."
-
-            # Get the full ConfigMap YAML
-            sudo KUBECONFIG=/etc/rancher/k3s/k3s.yaml \
-              kubectl -n kube-system get configmap coredns -o yaml > config.yaml
-
-            # Update the Corefile section
-            awk -v ip="$RUNNER_IP" '
-            /NodeHosts: \|/ {
-              print
-              getline
-              print "    " ip " harbor.machine"
-              print "    " ip " symphony.machine"
-              print
-              next
-            }
-            { print }
-            ' config.yaml > config-new.yaml
-
-            # Verify the change was made
-            if grep -q "harbor.machine" config-new.yaml && grep -q "symphony.machine" config-new.yaml; then
-              echo "✅ DNS entries added to ConfigMap"
-
-              # Apply the updated ConfigMap
-              sudo KUBECONFIG=/etc/rancher/k3s/k3s.yaml kubectl apply -f config-new.yaml
-
-              # Restart CoreDNS
-              sudo KUBECONFIG=/etc/rancher/k3s/k3s.yaml kubectl rollout restart deployment coredns -n kube-system
-              sudo KUBECONFIG=/etc/rancher/k3s/k3s.yaml kubectl rollout status deployment/coredns -n kube-system --timeout=60s
-
-              # Wait longer for DNS propagation
-              echo "⏳ Waiting for DNS propagation..."
-              sleep 15
-
-              echo "✅ CoreDNS configured successfully"
-              break
-            else
-              echo "⚠️ DNS entries not found in updated ConfigMap, retrying..."
-              sleep 5
-            fi
-
-            if [ $RETRY -eq 3 ]; then
-              echo "❌ Failed to configure CoreDNS after 3 attempts"
-              echo "ConfigMap contents:"
-              cat config-new.yaml
-              exit 1
-            fi
-          done
-
-
       - name: WFM-Client (Standalone Cluster) – Start
         working-directory: scripts
         run: |

docs/setup-guide.md

@@ -261,68 +261,21 @@ On each VM, you need to configure environment variables (settings that tell the
    cd $HOME/workspace/sandbox/scripts
    ```
 
-2. **Configure the domain/host(name) resolution in coredns**
-
-   The k3s based setups don't pick the changes from `/etc/hosts` system file, hence it is better to add hostname details in the the coredns config itself.
-
-   2.1. Fetch the coredns config first:
-   ```bash
-   sudo kubectl -n kube-system edit configmap coredns
-   ```
-
-   2.2. Then add only the highlighted lines in the `NodeHosts` section with your IP addresses in them and save:
-   ```yaml
-   apiVersion: v1
-   data:
-     Corefile: |
-       .:53 {
-         errors
-         health
-         ready
-         kubernetes cluster.local in-addr.arpa ip6.arpa {
-           pods insecure
-           fallthrough in-addr.arpa ip6.arpa
-         }
-         hosts /etc/coredns/NodeHosts {
-           ttl 60
-           reload 15s
-           fallthrough
-         }
-         prometheus :9153
-         forward . /etc/resolv.conf
-         cache 30
-         loop
-         reload
-         loadbalance
-         import /etc/coredns/custom/*.override
-       }
-       import /etc/coredns/custom/*.server
-     NodeHosts: |
-       20.11.000.000 harbor.machine # Newly added line to resolve harbor.machine
-       20.11.000.000 symphony.machine # Newly added line to resolve symphony.machine
-       10.0.0.11 margo-wfm-v10
-   ```
-
-   2.3. Then apply the changes:
-   ```bash
-   sudo kubectl -n kube-system rollout restart deployment coredns
-   ```
-
-3. **Start the device's Workload Fleet Management Client**
+2. **Start the device's Workload Fleet Management Client**
    ```bash
     sudo -E bash device-agent.sh k3s
    ```
    - Type `5` and press Enter
    - Choose: `Option 5: Device-agent-Start(k3s-device)`
 
-4. **Check device status**
+3. **Check device status**
    ```bash
     sudo -E bash device-agent.sh k3s
    ```
    - Type `7` and press Enter
    - Choose: `Option 7: Device-agent-Status`
 
-5. **View device logs**
+4. **View device logs**
    ```bash
    # View the logs (replace <pod-name> with actual pod name from above using #7)
    sudo kubectl logs -f <pod-name> -n default

scripts/device-agent.sh

@@ -115,6 +115,8 @@ source "${SCRIPT_DIR}/modules/harbor.sh"
 source "${SCRIPT_DIR}/modules/certificates.sh"
 source "${SCRIPT_DIR}/modules/agent.sh"
 source "${SCRIPT_DIR}/modules/observability.sh"
+source "${SCRIPT_DIR}/modules/dns-host-config.sh"
+
 
 
 export GOINSECURE='github.com/margo/*'
@@ -178,6 +180,9 @@ install_prerequisites() {
   if [ "$DEVICE_TYPE" = "k3s" ]; then
     setup_k3s
     configure_harbor_trust_for_k3s
+    echo "Waiting for k3s to stabilize..."
+    sleep 5
+    configure_coredns_hosts
   fi
 
   echo 'prerequisites installation completed.'

scripts/modules/dns-host-config.sh

@@ -0,0 +1,155 @@
+#!/bin/bash
+
+#------------------------------------------------------------------------------
+# Returns the IPv4 address of the specified hostname from /etc/hosts.
+#------------------------------------------------------------------------------
+get_ip_from_hosts() {
+    local hostname="$1"
+    local hosts_file="/etc/hosts"
+    local ip
+
+    if [[ ! -r "$hosts_file" ]]; then
+        echo "[ERROR] Unable to read ${hosts_file}." >&2
+        return 1
+    fi
+
+    ip=$(
+        awk -v host="$hostname" '
+            /^[[:space:]]*#/ { next }
+            NF >= 2 && $2 == host {
+                print $1
+                exit
+            }
+        ' "$hosts_file"
+    )
+
+    if [[ -z "$ip" ]]; then
+        echo "[ERROR] Host '${hostname}' not found in ${hosts_file}." >&2
+        return 1
+    fi
+
+    if [[ ! "$ip" =~ ^([0-9]{1,3}\.){3}[0-9]{1,3}$ ]]; then
+        echo "[ERROR] Invalid IPv4 address '${ip}' for '${hostname}'." >&2
+        return 1
+    fi
+
+    printf '%s\n' "$ip"
+}
+
+#------------------------------------------------------------------------------
+# Adds or updates NodeHosts entries in the CoreDNS ConfigMap.
+#------------------------------------------------------------------------------
+
+add_or_update_host() {
+        local ip="$1"
+        local host="$2"
+
+        if awk -v host="$host" '
+            /^[[:space:]]*#/ { next }
+            $2 == host { found=1 }
+            END { exit !found }
+        ' <<<"$updated"; then
+
+            updated=$(
+                awk -v ip="$ip" -v host="$host" '
+                    /^[[:space:]]*#/ {
+                        print
+                        next
+                    }
+
+                    $2 == host {
+                        print ip " " host
+                        next
+                    }
+
+                    {
+                        print
+                    }
+                ' <<<"$updated"
+            )
+
+        else
+            if [[ -n "$updated" ]]; then
+                updated+=$'\n'
+            fi
+            updated+="${ip} ${host}"
+        fi
+}
+
+configure_coredns_hosts() {
+    set -euo pipefail
+
+    local namespace="kube-system"
+    local configmap="coredns"
+
+    local harbor_host="${EXPOSED_HARBOR_HOST}"
+    local symphony_host="${WFM_HOST}"
+
+    local harbor_ip
+    local symphony_ip
+
+    local nodehosts
+    local updated
+
+    echo "[INFO] Validating dependencies..."
+
+    for cmd in kubectl jq awk sed; do
+        if ! command -v "$cmd" >/dev/null 2>&1; then
+            echo "[ERROR] Required command '$cmd' is not installed." >&2
+            return 1
+        fi
+    done
+
+    echo "[INFO] Reading IP addresses from /etc/hosts..."
+
+    harbor_ip=$(get_ip_from_hosts "$harbor_host")
+    symphony_ip=$(get_ip_from_hosts "$symphony_host")
+
+    echo "[INFO] Verifying CoreDNS ConfigMap..."
+
+    if ! kubectl -n "$namespace" get configmap "$configmap" >/dev/null 2>&1; then
+        echo "[ERROR] ConfigMap '${configmap}' not found in namespace '${namespace}'." >&2
+        return 1
+    fi
+
+    nodehosts=$(
+        kubectl -n "$namespace" get configmap "$configmap" \
+            -o jsonpath='{.data.NodeHosts}' 2>/dev/null || true
+    )
+
+    updated="$nodehosts"
+
+    add_or_update_host "$harbor_ip" "$harbor_host"
+    add_or_update_host "$symphony_ip" "$symphony_host"
+
+    updated=$(sed '/^[[:space:]]*$/d' <<<"$updated")
+
+    if [[ "$updated" == "$nodehosts" ]]; then
+        echo "[INFO] CoreDNS NodeHosts already up to date."
+        return 0
+    fi
+
+    echo "[INFO] Updating CoreDNS ConfigMap..."
+
+    kubectl -n "$namespace" patch configmap "$configmap" \
+        --type merge \
+        --patch "$(cat <<EOF
+{
+  "data": {
+    "NodeHosts": $(printf '%s' "$updated" | jq -Rs .)
+  }
+}
+EOF
+)"
+
+    echo "[INFO] Restarting CoreDNS..."
+
+    kubectl -n "$namespace" rollout restart deployment/coredns
+
+    echo "[INFO] Waiting for CoreDNS rollout to complete..."
+
+    kubectl -n "$namespace" rollout status deployment/coredns --timeout=180s
+
+    echo "[INFO] CoreDNS NodeHosts updated successfully."
+}
+