[add-topo] Set kernel.pty.max to 8192 (sonic-net#19054)

What is the motivation for this PR?
Support deploy thousands of ceos/net containers on a single server.

How did you do it?
Set kernel.pty.max to 8192 in add-topo ansible-playbook.

How did you verify/test it?
Verified by deploy physical testbed.

Signed-off-by: Guy Shemesh <[email protected]>

Author: lizhijianrd

ansible/roles/vm_set/tasks/main.yml

@@ -160,6 +160,16 @@
   become: yes
   when: host_distribution_version.stdout >= "20.04"
 
+- name: Set kernel.pty.max to 8192
+  become: true
+  sysctl:
+    name: kernel.pty.max
+    value: 8192
+    state: present
+    sysctl_set: true
+    reload: true
+    sysctl_file: /etc/sysctl.d/99-pty.conf
+
 - name: Update libvirt qemu configuration
   block:
   - name: Set user to root in qemu.conf