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Monday, February 19, 2018

VCN Local Peering in Oracle Cloud Infrastructure...

Whitepaper on inter node communications between different networks (VCNs) in Oracle Cloud Infrastructure.


Contents:



Summary:

Part-1: Configure instances to access Internet. we will create compartments, VCNs and Subnets.
Part-2: Configure Instances to access Internet in Primary & Secondary compartment. We will create Internet Gateway, Instances and configure Security Lists & Route tables.
Part-3: Setup VCN peering between instances. We will create Local Peering Gateways (LPG), establish connection between LPGs and Configure Route Tables.
Part-4: Configure password less SSH connection between instances. Generate SSH keys, Transfer SSH keys  between Instances and Configure Route tables.

Purpose of this document                                                  


In the current cloud computing world there is always a need to setup communication between instances residing in different VCNs to configure high availability for an application or due to 3 tier architecture models or for various other reasons. This document guides you through the necessary steps needed to establish communication between instances residing in different VCNs, separate compartments and in separate Availability Domains. This document also walks you through on how to create the following cloud resources and other important setups.
·         Compartments, Virtual Cloud Networks, Subnets, Setup Route Tables, Configure security rules.
·         Instances.
·         Internet Gateways
·         Access Internet from Oracle Cloud Infrastructure Instances.
·         Local Peering Gateways.
·         Setup Inter Node communication between Instances.
·         Setup Password less SSH connection between Instances.

Scope & Assumptions


Scope of this document is to provide the reader with quick steps on how to setup VCN local peering between Instances in two different VCNs. This document should not be used as a complete reference guide for any production deployments. Instructions/steps provided in this document are for informational and testing purposes only. The author is not responsible for any mistakes/damages/security flaws caused by the following steps. Configuring Peering between regions is beyond the scope of this document.

This document assumes that the reader understands Oracle Cloud infrastructure architecture and has sound networking knowledge. The reader should also have working cloud account with privileges to create network components like VCN, IGW, INSTANCES.

Virtual Cloud Network (VCN)

A VCN is a soft­­ware defined virtual network in Oracle Cloud Infrastructure. A VCN offers you complete control over your cloud network environment. VCN offers CIDR ranges from /16 to /30, and you can assign your own private IP addresses, create subnets, create route tables and firewalls. You can have multiple VCNs to provide grouping and isolation between related resources. The scope of VCN is limited to all Availability Domains(ADs) in a region.

VCN Peering

Peering is a process of connecting multiple VCNs so that traffic can be routed between them privately. By default, instances from one VCN cannot communicate to instances in another VCN. You can configure peering between VCNs using LOCAL Peering Gateways so that instances from one VCN can communicate with instance in another VCN as if they are in the same network. VCN peering is currently allowed between same tenants and within a single region.

Core components of a VCN

  • Subnet: A subnet is a range of IP addresses within a VCN providing logical isolation for resource groups.
  • Security List: A set of stateful virtual firewall rules associated with a subnet. Security Lists consists of Ingress (Inbound) and Egress (Outbound) firewall rules. Security lists are attached to an instance at the time of instance launch.
  • Route Table: A set of virtual route rules, viewed in table format.  Route table provides mapping for the network traffic from subnets to destination address via gateways.
  • DHCP Options: IP address of a custom DNS server provided during instance launch.
  • Internet Gateway: A software-defined virtual router providing a path for network traffic from your VCN to the public internet.
  • Local Peering Gateway: is a software-defined virtual router providing a path for network traffic from one VCN to another VCN. It is used for local VNC peering.

The Figure 1 outlines the VCN peering architecture and how its core components interact with each other.

Architecture:
Figure 1 VNC Local Peering Architecture


Billing for VCN

There is no charge for creating VCNs and using them. There are no data transfer charges for any communication among resources within a VCN.

Cloud Resources Assignments


Figure 2 shows cloud resource names, CIDR block ranges and IP addresses that have been used throughout this document.



  

Compartment – Root
Compartment - Secondary
VCN
 Primary
SecondaryVCN2
Subnet
PrimarySubnet1
SecondarySubnet1
InternetGateway
PrimaryIGW1
SecondaryIGW1
Local Peering Gateway
PrimaryLPG1
SecondaryLPG1
VCN CIDR
10.0.0.0/16
20.0.0.0/16
Subnet CIDR
10.0.0.0/24
20.0.0.0/24
Private IP
10.0.0.2
20.0.0.2
Public IP
129.213.45.153
129.213.40.193
Instance Name
PrimaryVM1
SecondaryVM1
Instance Shape
VMStandard2.1
VMStandard1.2


Figure 2 Cloud resources name assignments

As mentioned earlier, the goal of this document is to establish communication between two instances residing in two different Compartments, two different Virtual Cloud Networks and two different Availability Domains(ADs) using VCN Local Peering gateways. For this purpose, this document has been divided into the following four parts:
Part-1: Configure instances to access Internet. we will create a compartment, VCNs and Subnets
Part-2: Configure Instances to access Internet in Primary & Secondary compartment. We will create Internet  
             Gateway, Instances and configure Security Lists & Route tables.
Part-3: Setup VCN peering between instances. We will create Local Peering Gateways (LPG), establish  
             connection between LPGs and Configure Route Tables.
Part-4: Configure password less SSH connection between instances. Generate SSH keys, Transfer SSH keys
              between Instances and Configure Route tables.

PART-1

Step – 1: Create compartment


We will be using two compartments for our setup; root compartment and secondary compartment. Root compartment will be used as Primary compartment. Figure 3 highlights the steps for root compartment.  Primary cloud resources will be deployed in root compartment and all the secondary cloud resources will be deployed in Secondary compartment. Figure 4 specifys the steps for creating secondary compartment.


Figure 3 Create Compartment




Figure 4 Create Secondary compartment



Step – 2: Create Virtual Cloud Network


To create a virtual cloud network, under Primary compartment:
1.       click on Networking Tab
2.       click on create Virtual Cloud Network.

Figure 5 is for reference.



Figure 5 Create Virtual Cloud Network


To fill in the details the following steps will be followed:
                        1.      Compartment à root
2.      VCN name à  Primary
                   3.      Select Virtual Cloud Network Only.
     4.      CIDR Range à 10.0.0.0/16
                       5.      Click à  Create Virtual Cloud Network
Figure 6 is for reference.


Figure 6 VCN details


Step – 3: Create Subnet in Primary VCN


Create subnet with values shown in Figure 7, 8 and 9:
  1.      Compartment à root
  2.      SubnetName à Primarysubnet1
  3.      CIDR Range à 10.0.0.0/24
  4.      Select à Default DHCP options and Default security lists.
  5.      Click à  Create 



Figure 7 Subnet Creation



Figure 8 Create subnet with values



Figure 9 Security lists


Wait until you see that Subnet is created and turns the status of the subnet to Available. Figure 10 is for reference.
Figure 10 Subnet Creation Confirmation




PART-2


Step - 1: Create Internet Gateway


Select Primary (root) compartment à Internet Gateway à Create Internet Gateway

Figure 11 and 12 are for reference:





Figure 11 Create Internet Gateway
Provide the name as PrimaryIGW1 and click Create Internet Gateway. Make sure that PrimaryIGW1 is in Available state as shown in the Figure 13.




Figure 12 Name Internet Gateway



Figure 13 Internet Gateway creation confirmation




Step - 2: Configure Route Tables


Now we need to configure Route tables to allow network traffic to passthrough Internet Gateway. In our example we are using default Route tables and we will modify the default route table in our Primary VCN to allow internet traffic. Figure 14 is for reference.




Figure 14 Default Route Table for Primary VCN

 Select the Default Route Table for Primary VCN and edit Route Rules as shown in Figure 15 below.























Figure 15 Edit Route Rules for Default Route Table in Primary VCN

Click on “+ Another Route Rule” as shown in Figure 16



Figure 16 Add Route Rule for Default Route Table in Primary VCN




Figure 17 Add Route rule to allow internet traffic via Internet Gateway





Figure 18 Route rule addition confirmation.


Step – 3: Launch Instance


 Go to Primary (root) compartment and select Compute à Instances. Click on Launch Instance as shown in Figure 19.



Figure 19 Launch Instance in Primary Compartment.



Choose the following options for Instance Launch in Primary Compartment. Figure 20 is for reference

Instance Name                        à PrimaryVM1
Availability Domain                 à AD1
IMAGE SOURCE                        à  ORACLE PROVIDED IMAGE
IMAGE O.S                                à Oracle Linux 7.4
SHAPE TYPE                              à VIRTUAL MACHINE
SHAPE TYPE                              à VM.Standard2.1
VIRTUAL CLOUD NETWROK    à  Primary
SUBNET                                    à PrimarySubnet1
UPLOAD SSH KEYS                    à USER

Launch Instance.




Figure 20 Options for Instance creation



Step – 4:  Create VCN in Secondary compartment.

Now we will mimic and create cloud resources in Secondary compartment as we did in Primary Compartment. First, we will start by creating VCN - SecondaryVCN2 as shown in Figure 21 & Figure 22


Figure 21 Create VCN in Secondary Compartment

Change compartment to Secondary in the bottom left and select Virtual Cloud Networks. Click on Create Virtual Cloud Network.
Fill in the details as shown in Figure 22

1.      Compartment à Secondary

2.      VCN name à  SecondaryVCN2

3.      Select Virtual Cloud Network Only.

4.      CIDR Range à 20.0.0.0/16
5.      Click à  Create Virtual Cloud Network





Figure 22 Secondary VCN creation



Figure 23 Create Subnet in Secondary VCN2


In SecondaryVCN2 select Subnets and click on Create Subnet with the below values.
Create subnet with values shown in Figure 24.
·          Compartment à Secondary
·         SubnetName à Secondarysubnet1
·         CIDR Range à 20.0.0.0/24
·         Select à Default DHCP options and Default security lists.
·         Select à Default Security List for SecondaryVCN2
·         Click à Create 





Figure 24 Create Subnet Secondary subnet1

Step – 6: Create Internet Gateway in Secondary compartment



Select Secondary compartment à Internet Gateway à Create Internet Gateway


Figure 25 Create Internet Gateway






Figure 26 Create Internet Gateway in Secondary Compartment.

Provide the name as SecondaryIGW1 and click Create Internet Gateway. Make sure that SecondaryIGW1 is in Available state.

Step – 7: Configure Route Tables in Secondary Compartment

Now we need to configure Route tables to allow network traffic to passthrough Internet Gateway. In our example we are using default Route tables and we will modify the default route table in SecondaryVCN2 to allow internet traffic.





Figure 27 Configure Route Table in Secondary Compartment




Figure 28 Add Route rule to allow internet traffic via Secondary Internet Gateway.

Step – 8: Launch Instance in Secondary Compartment


Choose the Below options for Instance Launch in Secondary Compartment, Figure 29.

Instance Name                            - SecondaryVM1
Availability Domain                 -    AD1
IMAGE SOURCE                    -  ORACLE PROVIDED IMAGE
IMAGE O.S                              -  Oracle Linux 7.4
SHAPE TYPE                           -  VIRTUAL MACHINE
SHAPE TYPE                           -  VM.Standard2.1
VIRTUAL CLOUD NETWROK  -  Secondary
SUBNET                                  -  SecondarySubnet1
UPLOAD SSH KEYS              -   USER


Figure 29 Launch Instance in Secondary compartment.

Step – 9: Test Internet Traffic


Login into instances using their Public IPs as shown below in Figure 30 and ping any public URL. Here we will ping www.google.com and we should see the successful packet transfers. 



Figure 30 Login into Instances and Test internet traffic

PART-3


In this part, we will create Local Peering Gateways (LPG) in Primary & Secondary compartments, establish private connection between LPGs and Configure Route Tables to allow network traffic to pass through LPGs. The steps for doing so are listed below.


Step – 1: Creating Local Peering Gateway (LPG)

Select Primary (root) compartment à Networking à Virtual Cloud Networks à Primary VCN à Local Peering Gateway

Click Create Local Peering Gateway as shown in Figure 31



Figure 31 Create Local Peering Gateway






Figure 32 Create PrimaryLPG1 – Local Peering Gateway in Primary compartment


Now switch to Secondary compartment and create Local peering gateway as follows:
Select Secondary compartment -> Networking -> Virtual Cloud Networks -> SecondaryVCN2 -> Local Peering Gateway.
Click Create Local Peering Gateway as shown in Figure 33



Figure 33 Create Local Peering Gateway





Figure 34 Create SecondaryLPG1 – Local Peering Gateway in Secondary compartment

Confirm that the SecondaryLPG1 is created successfully and status is Available as shown in Figure35






Figure 35 Secondary Local Peering Gateway creation confirmation


Step – 2: Establish Connection Between LPGs


Switch to Primary (root) compartment à Networking à Virtual Cloud Networks à Primary VCN à Local Peering Gateway à Click Establish Connection. (Figure 36 and 37 are for reference)

 Figure 36 Establish Connection between Local Peering Gateways





Figure 37 Setup Connection with Secondary Local Peering Gateway

You need to establish connection only once between two LPGs and it doesn’t really matter which LPG you pick to establish the connection from.





Figure 38 Perring confirmation between Local Peering Gateways


Step – 3: Configure Route Tables


So far, we have created LPGs and bridged a connection between LPGs but the instances in the two VCNs cannot communicate yet due to the Firewall restrictions. In this section we will configure Route tables and modify Security Lists to ease Firewall restrictions and allow network traffic from the instances to passthrough Local Peering Gateway. In our example we are using default Route tables and we will modify the default route table in our Primary & Secondary VCN to allow destination LPG CIDR traffic to pass through.

Select Secondary compartment à Networking à Virtual Cloud Networks à SecondaryVCN2 à Route Tables à Default Route Table
Add new Route Rule to route network traffic from SecondaryLPG1 to destination CIDR block 10.0.0.0/24 as shown in Figure 39.





Figure 39 Add Route rule to route Secondary LPG traffic




Figure 40 Route rule addition confirmation for SecondaryLPG1 traffic





Figure 41 Add Route rule to route Primary LPG traffic


Select Primary (root) compartment à Networking à Virtual Cloud Networks à Primary VCN à Route Tables à Default Route Table.

Add new Route Rule to route network traffic from PrimaryLPG1 to destination CIDR block 20.0.0.0/24 as shown in Figure 42.





Figure 42 Add Route rule to allow PrimaryLPG1 traffic

Step – 4: Configure Security Lists


Now edit Default security list in SecondaryVCN2 to allow all protocols from CIDR block range 10.0.0.0/24 into SecondaryVCN2.




Figure 43 Security List modification in SecondaryVCN2

Select Secondary compartment  Networking  Virtual Cloud Networks  SecondaryVCN2 à Default Security List à Add Rule.  Add rule to allow all protocols from CIDR block range 10.0.0.0/24 into SecondaryVCN2 as shown in Figure 44.




Figure 44 Add security Rule in SecondaryVCN2


Now edit Default security list in Primary VCN to allow all protocols from CIDR block range 20.0.0.0/24 into primary VCN.



Figure 45 Modify Security List in Primary VCN


Select Primary (root) compartment à Networking à Virtual Cloud Networks à Primary VCN à Default Security List à Add Rule.

Add rule to allow all protocols from CIDR block range 20.0.0.0/24 into Primary VCN as shown in Figure 46.


Figure 46 Add security Rule in Primary VCN

Step – 5: Test VNC Local peering

Note down the public and Private IP addresses of instances in PrimaryVCN and SecondaryVCN.
Login into PrimaryVM1 as opc user and ping the private IP address of the SecondaryVM1 you should be able to see the packet response from SecondaryVM1.  


Figure 47 PrimaryVM1 IP addresses


[opc@primaryvm1 ~]$ ifconfig -a
ens3: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 9000
        inet 10.0.0.2  netmask 255.255.255.0  broadcast 10.0.0.255
        ether 02:00:17:01:9e:6d  txqueuelen 1000  (Ethernet)
        RX packets 56766  bytes 328814777 (313.5 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 48827  bytes 124483559 (118.7 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        loop  txqueuelen 0  (Local Loopback)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

[opc@primaryvm1 ~]$ ping 20.0.0.2
PING 20.0.0.2 (20.0.0.2) 56(84) bytes of data.
64 bytes from 20.0.0.2: icmp_seq=1 ttl=64 time=0.212 ms
64 bytes from 20.0.0.2: icmp_seq=2 ttl=64 time=0.175 ms
64 bytes from 20.0.0.2: icmp_seq=6 ttl=64 time=0.177 ms
64 bytes from 20.0.0.2: icmp_seq=7 ttl=64 time=0.140 ms
64 bytes from 20.0.0.2: icmp_seq=8 ttl=64 time=0.145 ms
^C
--- 20.0.0.2 ping statistics ---
8 packets transmitted, 8 received, 0% packet loss, time 6999ms
rtt min/avg/max/mdev = 0.140/0.173/0.212/0.025 ms



Figure 48 SecondaryVM1 IP addresses

[opc@secondaryvm1 ~]$ ifconfig -a
ens3: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 9000
        inet 20.0.0.2  netmask 255.255.255.0  broadcast 20.0.0.255
        ether 02:00:17:01:53:5a  txqueuelen 1000  (Ethernet)
        RX packets 57725  bytes 328343608 (313.1 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 54826  bytes 181204328 (172.8 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        loop  txqueuelen 0  (Local Loopback)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

[opc@secondaryvm1 ~]$ ping 10.0.0.2
PING 10.0.0.2 (10.0.0.2) 56(84) bytes of data.
64 bytes from 10.0.0.2: icmp_seq=1 ttl=64 time=0.222 ms
64 bytes from 10.0.0.2: icmp_seq=2 ttl=64 time=0.172 ms
64 bytes from 10.0.0.2: icmp_seq=3 ttl=64 time=0.166 ms
64 bytes from 10.0.0.2: icmp_seq=4 ttl=64 time=0.205 ms
64 bytes from 10.0.0.2: icmp_seq=5 ttl=64 time=0.157 ms
64 bytes from 10.0.0.2: icmp_seq=13 ttl=64 time=0.171 ms
^C
--- 10.0.0.2 ping statistics ---
13 packets transmitted, 13 received, 0% packet loss, time 11999ms
rtt min/avg/max/mdev = 0.137/0.172/0.222/0.027 ms




Figure 49 Inter instance communication via LPGs

PART - 4


Step – 1: Setup User equivalency or password-less ssh login between OCI instances


We will generate ssh rsa  keys without any passphrase for simplicity and then add the public key id_rsa.pub into PrimaryVM1’s ~/.ssh/authorized_keys file to enable password less login for opc user.

Step – 2: Generate SSH RSA Keys


[opc@secondaryvm1 ~]$ pwd
/home/opc
[opc@secondaryvm1 ~]$ ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/home/opc/.ssh/id_rsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/opc/.ssh/id_rsa.
Your public key has been saved in /home/opc/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:iOniHDTl09z/2kc9X5cw8tia9RmfmrcmW9jPZq0GT+w opc@secondaryvm1
The key's randomart image is:
+---[RSA 2048]----+
|                 |
|                 |
|    .            |
|   o = o   . o   |
|  o = + S   =.o..|
| . o .   . ..+*++|
|  o .     . +B.o@|
| o o       = .EBB|
|  o       ..o*B=+|
+----[SHA256]-----+

[opc@secondaryvm1 ~]$ cat .ssh/id_rsa.pub
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCap+PEKhwVbvP05Gikv6toUq6POzUmuwgh8FrnILBkCmKfWLQRChmcUNlCvEG7Wqc2SUW6lefHhNpcIkrT/Q/TDwkhVN5HMupgU0oJZEP1fUH/xj365deQJrZPWCa1ZzPGEozj76kcqYOqPMVSbtc0O4znuyXvFeZBcwmFiwzp0LcAOeJlfvTKBXe0y3+7CHYgJzjMgfPZgPbMUu40LdBlHS3kEVkRwWlOSJFxjGrZyl0FbX74jHFQ1RDy/LYjXeZvZdyqjYdpwNw6t0LEFHjYAy50gOkrw9SDwsDR2QJOxXiZ7ccz0WoBSI2Hp9FQXmlnk7stWS0t9xNe2XevRdsF opc@secondaryvm1

Either scp public key or copy and paste into authorized_keys file in primaryVM1 host.
[opc@primaryvm1 ~]$ vi .ssh/authorized_keys

[opc@secondaryvm1 ~]$ ssh 10.0.0.2
The authenticity of host '10.0.0.2 (10.0.0.2)' can't be established.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '10.0.0.2' (ECDSA) to the list of known hosts.
Last login: Fri Feb 16 21:38:30 2018 from ool-18b8eaa0.dyn.optonline.net
Generate SSH RSA keys on PrimaryVM1 and add the public key id_rsa.pub into SecondaryVM1’s ~/.ssh/authorized_keys file to enable password less login for opc user.
 [opc@primaryvm1 ~]$ ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/home/opc/.ssh/id_rsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/opc/.ssh/id_rsa.
Your public key has been saved in /home/opc/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:SNeDgqryhoIYc1w6983KFrU59ajye5RAEVnGqemYFzo opc@primaryvm1
The key's randomart image is:
+---[RSA 2048]----+
|        o*o.     |
|     .  o+o      |
|    . o.ooo      |
| ..o  .*S* +     |
|o.= . E * + .    |
|== o . * +       |
|*..  .+ + .      |
|...  .o+oo       |
+----[SHA256]-----+

[opc@primaryvm1 ~]$ cat ~/.ssh/id_rsa.pub
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDBeF90LFhO/QF/u0uEVnxKEX6z3Q09XZIjsPpN1F+RVZrJ47+9qNytPKFqg8OErUuBb5iUK9VyFG2fmLJQgGgARGZXy4SlEoW8GBq/CIQbHF5JLcDcWVrUuNTu2QbKZKD3bJq7+zG+P28YdLs8jDprVHhkKiNK1PPQpgnVLAGRYTbDhsAX9zO944FCCrbsKDVSVVdR1ySRryvAveU4j8r1HsjqgYvPzLb8Dmlhgnz9b336JGOicJ1Wy+AunHSdUAJgVg4gG6qJWA2M6Vi3ePUn5ImipAhJ0WGDRhbP/7Vz+51chiUPyceG2VnnFFSHuLQiuFrPm7iBPRvfuTysV2ir opc@primaryvm1

[opc@primaryvm1 ~]$ vi .ssh/authorized_keys
[opc@primaryvm1 ~]$ ssh 20.0.0.2
The authenticity of host '20.0.0.2 (20.0.0.2)' can't be established.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '20.0.0.2' (ECDSA) to the list of known hosts.
Last login: Fri Feb 16 21:38:32 2018 from ool-18b8eaa0.dyn.optonline.net








2 comments:

Senthilkumar Kandasamy said...

Dear Sameer,

Your "VCN Local Peering in Oracle Cloud Infrastructure" explanation is good...

Thanks for the post!!!

Senthilkumar Kandasamy said...

Hi Sameer,

can I get any document for "Oracle Cloud Infrastructure 2018 Certified Architect Associate" and "Oracle Cloud Infrastructure Classic 2018 Certified Architect Associate" exam..

I took exam last week, but scored only 56%..