Friday, February 21, 2020
Thursday, February 20, 2020
Routing - Administrative distance
Administrative distance
https://en.wikipedia.org/wiki/Administrative_distance
External BGP - 20
Internal BGP - 200
https://en.wikipedia.org/wiki/Administrative_distance
External BGP - 20
Internal BGP - 200
Monday, February 10, 2020
Host cannot communicate with one or more other nodes in the vSAN enabled cluster
Ping between nodes was working so it was not a physical network issue. This is the lab environment so all services (mgmt, vMotion, vSAN) are enabled on single VMKNI (vmknic0).
So what's the problem?
I did some google searching and found that some people were experiencing problems with vSAN unicast agents.
Here is the command to list of unicast agents on vSAN node
esxcli vsan cluster unicastagent list
Grrrr. The list is empty!!!! On all ESXi hosts in my 3 nodes vSAN cluster.
Let's try to configure it manually.
Each vSAN node should have a connection to agents on other vSAN nodes in the cluster.
For example, one vSAN node from 4-node vSAN Cluster should have 3 connections
We need the get local UUID of the cluster node.
So here are my nodes
n-esx08 - 192.168.11.108 - 5df792b0-f49f-6d76-45af-005056a89963
n-esx09 - 192.168.11.109 - 5df792b0-f49f-6d76-45af-005056a89963
n-esx10 - 192.168.11.110 - 5df792b0-f49f-6d76-45af-005056a89963
And the problem is clear. All vSAN nodes have the same UUID.
Why? Let's check ESXi system UUIDs on each ESXi host.
So the root cause is obvious. I use nested ESXi to test vSAN and I forgot to regenerate system UUID after the clone. The solution is easy. Just delete UUID from /etc/vmware/esx.conf and restart ESXi hosts.
You can do it from command line as well
sed -i 's/system\/uuid.*//' /etc/vmware/esx.conf
reboot
So we have identified the problem and we are done. After ESXi hosts restart vSAN Cluster Nodes UUIDs are changed automatically and vSAN unicastagents are automatically configured on vSAN nodes as well.
However, if you are interested in how to manually add a connection to a unicast agent on a particular node, you would execute the following command
esxcli vsan cluster unicastagent add –a <ip address unicast agent> –U <supports unicast> –u <Local UUID> -t < type>
Anyway, such a manual configuration should not be necessary and you should do it only when instructed by VMware support.
Hope this helps someone else in VMware community.
So what's the problem?
I did some google searching and found that some people were experiencing problems with vSAN unicast agents.
Here is the command to list of unicast agents on vSAN node
esxcli vsan cluster unicastagent list
Grrrr. The list is empty!!!! On all ESXi hosts in my 3 nodes vSAN cluster.
Let's try to configure it manually.
Each vSAN node should have a connection to agents on other vSAN nodes in the cluster.
For example, one vSAN node from 4-node vSAN Cluster should have 3 connections
[root@n-esx04:~] esxcli vsan cluster unicastagent list
NodeUuid IsWitness Supports Unicast IP Address Port Iface Name Cert Thumbprint
------------------------------------ --------- ---------------- -------------- ----- ---------- -----------------------------------------------------------
5e3ec640-c033-7c7d-888f-00505692f54d 0 true 192.168.11.105 12321 18:F3:B7:9F:66:C4:C4:3E:0F:7D:69:BB:55:92:BC:A3:AC:E4:DD:5F
5df792b0-f49f-6d76-45af-005056a89963 0 true 192.168.11.107 12321 20:4C:C1:48:F5:2D:04:16:55:F1:D3:F1:4C:26:B5:C4:23:E5:B4:12
5e3e467a-1c1b-f803-3d0f-00505692ddc7 0 true 192.168.11.106 12321 53:99:00:B8:9D:1A:97:42:C0:10:C0:AF:8C:AD:91:59:22:8E:C9:79
[root@n-esx08:~] esxcli vsan cluster get
Cluster Information
Enabled: true
Current Local Time: 2020-02-11T08:32:55Z
Local Node UUID: 5df792b0-f49f-6d76-45af-005056a89963
Local Node Type: NORMAL
Local Node State: MASTER
Local Node Health State: HEALTHY
Sub-Cluster Master UUID: 5df792b0-f49f-6d76-45af-005056a89963
Sub-Cluster Backup UUID:
Sub-Cluster UUID: 52c99c6b-6b7a-3e67-4430-4c0aeb96f3f4
Sub-Cluster Membership Entry Revision: 0
Sub-Cluster Member Count: 1
Sub-Cluster Member UUIDs: 5df792b0-f49f-6d76-45af-005056a89963
Sub-Cluster Member HostNames: n-esx08.home.uw.cz
Sub-Cluster Membership UUID: f8d4415e-aca5-a597-636d-005056997c1d
Unicast Mode Enabled: true
Maintenance Mode State: ON
Config Generation: 7ef88f9d-a402-48e3-8d3f-2c33f951fce1 6 2020-02-10T21:58:16.349
So here are my nodes
n-esx08 - 192.168.11.108 - 5df792b0-f49f-6d76-45af-005056a89963
n-esx09 - 192.168.11.109 - 5df792b0-f49f-6d76-45af-005056a89963
n-esx10 - 192.168.11.110 - 5df792b0-f49f-6d76-45af-005056a89963
And the problem is clear. All vSAN nodes have the same UUID.
Why? Let's check ESXi system UUIDs on each ESXi host.
[root@n-esx08:~] esxcli system uuid get
5df792b0-f49f-6d76-45af-005056a89963
[root@n-esx08:~]
[root@n-esx09:~] esxcli system uuid get
5df792b0-f49f-6d76-45af-005056a89963
[root@n-esx09:~]
[root@n-esx10:~] esxcli system uuid get
5df792b0-f49f-6d76-45af-005056a89963
[root@n-esx10:~]
So the root cause is obvious. I use nested ESXi to test vSAN and I forgot to regenerate system UUID after the clone. The solution is easy. Just delete UUID from /etc/vmware/esx.conf and restart ESXi hosts.
![]() |
| ESXi system UUID in /etc/vmware/esx.conf |
You can do it from command line as well
sed -i 's/system\/uuid.*//' /etc/vmware/esx.conf
reboot
So we have identified the problem and we are done. After ESXi hosts restart vSAN Cluster Nodes UUIDs are changed automatically and vSAN unicastagents are automatically configured on vSAN nodes as well.
However, if you are interested in how to manually add a connection to a unicast agent on a particular node, you would execute the following command
esxcli vsan cluster unicastagent add –a <ip address unicast agent> –U <supports unicast> –u <Local UUID> -t < type>
Anyway, such a manual configuration should not be necessary and you should do it only when instructed by VMware support.
Hope this helps someone else in VMware community.
Friday, February 7, 2020
Saturday, February 1, 2020
macOS – SSH Error ‘No Matching Exchange Method Found’
Davids-MacBook-Pro:~ dpasek$ ssh admin@192.168.4.253
Unable to negotiate with 192.168.4.253 port 22: no matching key exchange method found. Their offer: diffie-hellman-group1-sha1,
Solution ...
https://www.petenetlive.com/KB/Article/0001245
Unable to negotiate with 192.168.4.253 port 22: no matching key exchange method found. Their offer: diffie-hellman-group1-sha1,
https://www.petenetlive.com/KB/Article/0001245
Solution
This is not Apple’s fault, it’s OpenSSH version 7. SHA1 is weak, so support for it has been removed. Which is fine, but all my clients Cisco Firewalls/Routers/Switches are probably all using RSA/SHA1. So until they re all updated I’m going to need to re-enable SHA1.
Open a terminal windows and execute the following;
sudo nano /etc/ssh/ssh_config
ENTER YOUR PASSWORD
Locate the line ‘ # MACs hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-ripemd160′ and remove the Hash/Pound sight from the beginning.
Locate the line ‘ # Ciphers aes128-ctr,aes192-ctr,aes256-ctr,aes128-cbc,3des-cbc’ and remove the Hash/Pound sight from the beginning.
Then paste the following on the end;
HostkeyAlgorithms ssh-dss,ssh-rsaKexAlgorithms +diffie-hellman-group1-sha1
Thursday, January 30, 2020
VMware Cloud Foundation - Overview
Overview
- VCF lze postavit ve dvou deployment modelech
- Standardní – to je jedna Management domain (minimum 4 hosty, maximum 64) + až 15 oddělených Workload domains (minimum 3 hosty per pro každou, maximum 64).
V tomto modelu je tedy potřeba mimimálně 7 hostů (4 + 3), oddělení workloadu ja na úrovni samotných hostů.
- Konsolidovaný - Management a Workload domains je společná, minimální počet jsou 4 hosty a lze rozšiřovat až na 64 hostů.
Oddělení workloadu je v tomto modelu na úrovni Resource pool-ů.
Tento model nepodporuje automatický deployment VMware Enterprise PKS a VMware Horizon.
V budoucnu lze přejít z konsolidovaného modelu na standardní.
- vCenter
- Licence vCenter není součástí balíku VCF a je potřeba zajistit samostatně
- Pro VCF je potřeba jedna licence vCenter (platí pro oba deployment modely).
V případě Standardního modelu je součástí každé Workload domain vlastní instance vCenter serveru (ty se ale nelicencují, opět stačí jedna licence).
- Není podporováno použití existujícího/externího vCenter serveru.
- Hardware
- Management domain případně Konsolidovaný model musí mít pod sebou vSAN. Ve Standardním modelu jsou pro Workload domény podporovány i externí storage (NFS, FC SAN).
- Do verze VCF 3.9.1 bylo možné pro komunikaci mezi hosty (management, vSAN, vMotion) vyžít pouze dvě fyzické NIC, od verze 3.9.1 je možné použít až 4 pNICs, pokud je použito NSX-V nebo až 6 pNICs, pokud je použito NSX-T.
- Networking
- Management domain a obecně konsolidovaný model podporuje pouze NSX-V
- Do Workload domain lze zvolit zda bude použito NSX-V nebo NSX-T
- VCF od verze 4.0 by měl podporovat již pouze NSX-T (Přechod z NSX-V by měl být vyřešen při upgrade)
Sunday, January 26, 2020
Windows 10 - ICMP Allow incoming V4 echo request
Command
netsh advfirewall firewall add rule name="ICMP Allow incoming V4 echo request" protocol=icmpv4:8,any dir=in action=allow
Source: https://www.howtogeek.com/howto/windows-vista/allow-pings-icmp-echo-request-through-your-windows-vista-firewall/
Alternativ way over GUI
Windows Firewall
Search for Windows Firewall, and click to open it.
Click Advanced Settings on the left.
From the left pane of the resulting window, click Inbound Rules.
In the right pane, find the rules titled File and Printer Sharing (Echo Request - ICMPv4-In).
Right-click each rule and choose Enable Rule.
Source: https://kb.iu.edu/d/aopy
netsh advfirewall firewall add rule name="ICMP Allow incoming V4 echo request" protocol=icmpv4:8,any dir=in action=allow
Source: https://www.howtogeek.com/howto/windows-vista/allow-pings-icmp-echo-request-through-your-windows-vista-firewall/
Alternativ way over GUI
Windows Firewall
Search for Windows Firewall, and click to open it.
Click Advanced Settings on the left.
From the left pane of the resulting window, click Inbound Rules.
In the right pane, find the rules titled File and Printer Sharing (Echo Request - ICMPv4-In).
Right-click each rule and choose Enable Rule.
Source: https://kb.iu.edu/d/aopy
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