Year: 2018

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Changing Hostname in xCAT 2.14

All activities to be triggered from Master Node 1

Step 1:

# ssh nodename

Step 2:

# /etc/sysconfig/network | Add HOSTNAME=newnodename						
# /etc/hostname | Add newnodename

exit

Step 3:
Remove Old Provision Environment

# makedns -d nodename /*Remove the nodes from DNS configuration*/
# makedhcp -d nodename /*Remove the nodes from the DHCP configuration*/

Step 4:
Change Definition

# chdef -t node -o oldnodename -n newnodename /*Change the hostname in the xCAT database*/
# chdef -t node -o newnodename bmc=oldbmcname /*Re add the bmc name in the xCAT database*/

Step 5:
Change the hostname and IP address in the /etc/hosts file

# makehosts newnodename

Step 6:

# makedns -n /*Configure the new names in DNS*/
# makedhcp -a /*Configure the new names in DHCP*/
# makeconfluentcfg /*Update Console Server*/

Step 7:
Reboot Updated Server

Step 8:
After you repeat Step – 1 to Step – 7 for all nodes On the primary management node.
Run

# pscp /etc/hosts all:/etc/

to copy the hosts file to all the nodes except the new node, because the new node need password authentication at this point.

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SSH Login without Password

The SSH daemon validates SSH client access by Linux system verification via /etc/passwd, or by public/private key cryptography approach.

By using the public/private cryptography approach, we can do a SSH without password.

In my write-up it is for root-to-root connection. You can use it for user connections.

Steps 1: At the Host Machine

  1. Logon to the root home directory.
  2. Make sure the hidden .ssh directory has the permission 700. If not execute the command 
    # chmod 700 .ssh
  3. Change Directory to .ssh directory by executing the command 
    # cd .ssh
  4. Generate the public-private keys using the ssh-keygen command. 
    # ssh-keygen -t rsa
  5. The resulting file id_rsa and id_rsa.pub rsa type public key 
    # ssh-copy-id -i ~/.ssh/id_rsa.pub remote-host

    (ssh-copy-id appends the keys to the remote-host’s .ssh/authorized_key)

Step 2: At the Remote Machine,

  1. Test it out on the remote server 
    # ssh remote-host

References

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Using dmidecode to find hardware information

Taken from the Manual Page

dmidecode is a tool for dumping a computer’s DMI (some say SMBIOS) table contents in a human-readable format. This table contains a description of the system’s hardware components, as well as other useful pieces of information such as serial numbers and BIOS revision.

 

Option 1: Getting DMI Type

[root@my-node1 ~]# dmidecode -t
dmidecode: option requires an argument -- 't'
Type number or keyword expected
Valid type keywords are:
bios
system
baseboard
chassis
processor
memory
cache
connector
slot

 

Option 2: DMI TYPES (From MAN Page)

DMI TYPES
The SMBIOS specification defines the following DMI types:

Type Information
────────────────────────────────────────────
0 BIOS
1 System
2 Baseboard
3 Chassis
4 Processor
5 Memory Controller
6 Memory Module
7 Cache
8 Port Connector
9 System Slots
10 On Board Devices
11 OEM Strings
12 System Configuration Options
13 BIOS Language
14 Group Associations
15 System Event Log
16 Physical Memory Array
17 Memory Device
18 32-bit Memory Error
19 Memory Array Mapped Address
20 Memory Device Mapped Address
21 Built-in Pointing Device
22 Portable Battery
23 System Reset
24 Hardware Security
25 System Power Controls
26 Voltage Probe
27 Cooling Device
28 Temperature Probe
29 Electrical Current Probe
30 Out-of-band Remote Access
31 Boot Integrity Services
32 System Boot
33 64-bit Memory Error
34 Management Device
35 Management Device Component
36 Management Device Threshold Data
37 Memory Channel
38 IPMI Device
39 Power Supply
40 Additional Information
41 Onboard Devices Extended Information
42 Management Controller Host Interface

 

Option 3 – Using Keyword types

Keywords can be used instead of type numbers with --type. Each keyword is equivalent to a list of type numbers:

Keyword Types
──────────────────────────────
bios 0, 13
system 1, 12, 15, 23, 32
baseboard 2, 10, 41
chassis 3
processor 4
memory 5, 6, 16, 17
cache 7
connector 8
slot 9

Keywords are matched case-insensitively. The following command lines are equivalent:

· dmidecode --type 0 --type 13
· dmidecode --type 0,13
· dmidecode --type bios
· dmidecode --type BIOS

 

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Mellanox SN2100 Ethernet Bundle Configurator

Mellanox has a Ethernet Configurator which you can even use for other model.

Here’s how it works:
Choose the following:
1. Choose the setup

  • 1 switch
  • 2 switches connected with mLAG
  • 5 switches: testing both mLAG as well as leaf spine (BGP/ECMP) – simple L3/VTEP/VXLAN Routing (VXLAN on Cumulus only for now)

2. Choose the speed of the host/NIC

  • 10/25/100GbE

3. Choose the operating system

  • ONYX
  • Cumulus Linux

What you get is:
1. Topology: how to connect, which specific ports should be used

2. Solution brief for the selected scenario

3. One Click Configuration files:

  • For the CLI guys: running config
  • For the Ansible guys: Ansible playbooks (ONYX Ansible for mLAG and L3 will be added soon)