fix: fetch vLLM logs and system metrics to local results in auto playbook

The llm-benchmark-auto playbook was collecting vLLM container logs and
system metrics on the DUT but never fetching them back to the controller.
This resulted in only benchmark results appearing in the local results
directory. Added fetch tasks to retrieve vLLM server logs and system
metrics alongside benchmark results.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
Signed-off-by: Maryam Tahhan <mtahhan@redhat.com>

Author: maryamtahhan

automation/test-execution/ansible/llm-benchmark-auto.yml

@@ -266,6 +266,12 @@
 
   tasks:
     - block:
+        - name: Ensure log directory exists on DUT
+          ansible.builtin.file:
+            path: "{{ log_dir }}"
+            state: directory
+            mode: "0755"
+
         - name: Get vLLM container logs
           ansible.builtin.command:
             cmd: "podman logs {{ vllm_container_name }}"
@@ -277,6 +283,32 @@
             content: "{{ vllm_logs.stdout }}"
             dest: "{{ log_dir }}/vllm-{{ core_configuration.name }}-{{ test_run_id }}.log"
 
+        - name: Collect system metrics snapshot
+          ansible.builtin.shell: |
+            echo "=== CPU Info ===" > {{ log_dir }}/system-metrics-{{ test_run_id }}.log
+            lscpu >> {{ log_dir }}/system-metrics-{{ test_run_id }}.log
+            echo "" >> {{ log_dir }}/system-metrics-{{ test_run_id }}.log
+            echo "=== Memory Usage ===" >> {{ log_dir }}/system-metrics-{{ test_run_id }}.log
+            free -h >> {{ log_dir }}/system-metrics-{{ test_run_id }}.log
+            echo "" >> {{ log_dir }}/system-metrics-{{ test_run_id }}.log
+            echo "=== Container Stats ===" >> {{ log_dir }}/system-metrics-{{ test_run_id }}.log
+            podman stats --no-stream {{ vllm_container_name }} >> {{ log_dir }}/system-metrics-{{ test_run_id }}.log 2>&1 || true
+          args:
+            executable: /bin/bash
+          changed_when: false
+
+        - name: Fetch vLLM logs to local results
+          ansible.builtin.fetch:
+            src: "{{ log_dir }}/vllm-{{ core_configuration.name }}-{{ test_run_id }}.log"
+            dest: "{{ playbook_dir }}/../../../results/llm/{{ test_model | replace('/', '__') }}/{{ workload_type }}-{{ test_run_id }}/vllm-server.log"
+            flat: true
+
+        - name: Fetch system metrics to local results
+          ansible.builtin.fetch:
+            src: "{{ log_dir }}/system-metrics-{{ test_run_id }}.log"
+            dest: "{{ playbook_dir }}/../../../results/llm/{{ test_model | replace('/', '__') }}/{{ workload_type }}-{{ test_run_id }}/system-metrics.log"
+            flat: true
+
       when: hostvars['localhost']['vllm_mode'] | default('managed') == 'managed'
 # ==============================================================================
 # STEP 8: Optional Cleanup (Managed Mode Only)