Some days back, I was having a conversation with a friend about the recent CVEs that impact the firmware of several physical machines. HP usually will release several vulnerability alerts and it is very important to patch your firmware. You might also notice that the mitigation happens at CPU levels such as AMD or Intel. In this blog post, I will focus on one of the very basic ways to update your firmware. Prior before upgrading, its important to make a checklist. My HP Proliant Gen9 is actually an ESXi on VMware infrastructure. You can view the step by step actions below and pause the video at any time. I have blurred some information for security purpose such as the name of servers, IPs, Logins, etc..
A basic checklist can be considered as follows:
How many and size of the VMs on production.
The consistency of the Firmware provided by HP.
Logins and Passwords for the HP ILO, vCenter, Virtual Machines running, etc..
Java or Dot Net framework for accessing the ILO.
Where is the storage node of the virtual machines?
Load on the cluster or the ESX itself.
The expected amount of time during migration.
The output of the update (Correction of bugs, New feature, etc..).
1. Prior before upgrading the firmware, you need to make a survey about the oversized VMs. Consider performing a manual migration before activating the maintenance mode. Then, enter maintenance mode, all the virtual machines in the cluster should migrate to other physical machines in the cluster. We assume that the datastore of each machine is not on the physical machine itself which is not recommended.
2. Once all virtual machines migrated to other ESXi hosts, connect to the HP ILO onboard administrator interface. Consider checking the health status of other ESXi hosts on your chassis.
3. Also consider, verifying the system information of your ESXi host (HP physical machine).
4. On the ‘information’ tab, click on ‘system information’, you will notice the field ‘Integrated remote console’. You can choose any framework whether Java or .Net to open the console.
5. Once connected, you should be able to see the following screen.
6. From vCenter, upload the image file which constitutes of the patch for the new firmware.
7. On vCenter, right click on the physical machine, then ‘reboot’. Consider checking the grey bar that is now blinking on the left just below the ‘<F2> tag ‘at the bottom on the ESXi console.
8. By the time, you should also notice that you have been logout on vCenter.
9. Normally, after a few minutes, the server will reboot showing the HP Enterprise logo followed by other system information, then you will notice a screen that with four key options below: F9 (System Utilities), F10 (Intelligent Provisioning), F11 (Boot Menu), and F12 (Network Boot). Hit the F9 button to enter ‘System Utilities’.
10. Choose the ‘one-time boot menu’ option. Then go to the USB virtual disk that you have mounted at step 6 and hit ‘Enter’.
11. By now you should notice the installation of the firmware in progress. This might take a considerate amount of time. Monitor the installation.
12. After extracting the iso file, it will go through three steps: Inventory, Review, and Deployment.
13. You can also monitor for the ‘blink’ message on the HP Onboard Administrator interface which means that the upgrade has not completed yet.
14. Once, the UID state is off, you can remove the server from maintenance. On vCenter, right click on the server, and click on ‘Exit maintenance mode’.
15. Several machines will now join the ESXi host which has been added back to the cluster through an election process.
If you are interested more on the election process and how High Availability works, please check the article ‘VMware vSphere High Availability‘ which I published several months back.
All steps from 1 to 15 have been described in the video below. If you like the article please click on the like button and share.
The Internet is growing. In case you are not on IPv6, for sure one day, you might need to migrate from IPv4 to IPv6. Now what kind of methodology you would apply whether a dual stack or a direct changeover depends upon a rigid observation and analysis of the network infrastructure. But, it should no more be taken as a complexity. Since a few years, many companies, government bodies, ISPs, and others are moving towards IPv6. Some are adopting dual stack. IPv6 can be said to be version 2 of the Internet. In this blog post, I will make my best to shed some basics and simple way to understand the features and benefits when using IPv6. I will also contrast it with IPv4. For research purpose, I have perused several books and blogs over the Internet and, same are referenced below. One of the challenges in Africa is to enable the smooth transition to IPv6. Whilst others are doing dual stack, others have successfully migrated the whole network infrastructure to IPv6. IPv4 has been created in the early ’80s. The Internet growth which is so huge and it will definitely need to move ahead with modern technology IPv6 running at its core. I had always admired one of the modern futurist physicist, Dr. Michio Kaku who said that “In the future, the Internet might become a brain“.
So why do we really need IPv6?
Besides, from the growth of the Internet and the scarcity of IPv4 addresses, we all knew that in IPv4, the network has been divided into two parts which are the Private IPs and the Public IPs allocation. And, those two segments which are Interconnected required NAT configuration. This breaks the contiguous of the Internet. Another reason is that there is no security in IPv4 at its core. Of course, there are other strategies to secure an IPv4 network. When it comes to data prioritization, it cannot be done at the core of IPv4 which means that there is not much of Quality of Service (QoS). In IPv4, we can configure or assigned an IP to a device or simply use an address configuration mechanism such as DHCP. But, the moment DHCP is down, we land into a problem. Here is the catch, this means that there is no way to make a device to be assigned a globally unique address. So, that’s why we need IPv6. Well, wait… What happened to IPv5 ? and what about IPv1, IPv2, and IPv3?
What happened to IPv1, IPv2, IPv3, and IPv5?
Have a look at the diagram below which makes it pretty easy to understand:
So, IPv0, IPv1, IPv2, and IPv3 were used in the development testing phase. Ipv5 was used while doing the Stream experimentation of the Internet.
Features of IPv6
There is no backward compatibility when using IPv6, but, the basic functions remain the same, and the features have been changed completely. Since IPv4 is a 32-bit address and IPv6 is a 128-bit address, just imagine how much bigger it is. When compared to an IPv4 address bit, IPv6 has four times more bits. We can say that there are more than 1500 IP addresses per square meter on earth.
Another feature of the IPv6 is about the header which is twice the size of IPv4.
In IPv6, there is also end-to-end connectivity which means that NAT is not required for the continuity of the Internet. Every host can reach another host over the Internet.
Other features are “auto-configuration” which can be either stateful or stateless. Stateless is a mechanism that does not require any intermediate support in the form of DHCP for IP assignment whereas Stateful serves IP addresses from a pool. Also to take into consideration is “faster routing”. In IPv6, the routing information is stored in the first part of the header which makes routing decisions faster by the router. Another feature is IPSec (IP Security). It creates an end-to-end tunnel between the source and the target though it is optional. “No Broadcast” is another feature within IPv6. Using an IPv4 network, you will notice during the IP Address configuration, the clients need to broadcast to the DHCP. In IPv6, the client doesn’t need to broadcast and instead will multicast to communicate with machines over the network. It is important to understand the difference between ‘broadcast’ (one-to-all) and ‘multicast'(one-to-many). In broadcast, clients will send messages to all hosts on the network, whereas in multicast, messages are sent to a group of stations. This allows the building of distribution networks where group management is required. IPv6 does not limits itself to multicast but also bring the ‘unicast’ (one-to-one) feature. This is used especially between routers which need to communicate to a specific router. However, if you have several routers nearby and you can choose any routers for communication, let’s say for a CDN purpose, we can use the anycast method to process efficiency packet routing.
Reading IPv6 addressing
Now, that you have grasped the basic concepts of IPv6 and why we need it, let’s see how to read IPv6. An IPv6 address is made up of 128-bits divided into 16-bits blocks. Each block is then converted into 4-digits hexadecimal numbers separated by colon symbol. For example, this is an IPv6 address in binary:
Since we have three series of zeros, it can be escaped between the two colons symbols. Leading zeros in the third block will result in 30. In case, you had one block of zeros, use one zero in the hexadecimal IP address. When converted to hexadecimal it is:
Let’s get into more details. There are two rules when reading an IPv6 address.
Rule1: Leading zeros should be discarded. As we can see in the 3rd block of the IPv6 address above i.e; 0000000000110000 when converted it is written as 30, because it can be read as 110000. Here is a video on how to convert Binary to Hexadecimal.
Rule2: If two or more blocks contain consecutive zeros, omit them all and replace by double colons signs. Example the three blocks of zeros in purple above have been replaced as “::“, However, if there is a single block of zero, use 0 in the IPv6 address.
Assignment of IPv6 address
Similar to IPv4, we need to understand how to identify the number of networks and hosts in IPv6. Let’s take an example from a generic unicast address which uses 64-bits as network ID and 64-bits as hosts ID. Please note from the picture below the 64-bits in the network has been shared in three distinctive fields in the IPv6 packet structure.
At this stage, it should be clear how a generic unicast address has been designed. Now, another important point is the IPv6 address scope. A scope is a region where an IPv6 address can be defined as a unique identifier of a network interface. As we can see below, there are three scopes, Global Unicast Address, Unique Local, and Link Local.
The Global Unicast Addressis routed and is reachable across the Internet. Also. the prefix for global routing prefix in IPv6 has been assigned by the Internet Assigned Number Authority – IANA, so that by only looking at the prefix of an IPv6 address, you can determine if its global or not. In the picture below, you can see the first 3 bits within the global prefix. Remember, that this is unique globally.
Then, comes the Site level aggregator – SLA which is the subnet ID assigned to the customer by the service provider. This follows by the LAN id that is used by the customer and is free to manipulate. This address is globally unique.
Let’s take a look at a Unique Local Unicast Address. It looks like private IP addresses and is used for local communication intersite usually in a LAN and for VPN purpose. It is not routable on the Internet.
The last one is the link local unicast address. This is used for communication between two IPv6 devices on the same link. By default, it is automatically assigned by the device as soon as IPv6 is enabled, and it is not routable. These types of IP addresses are identified by the first 10-bits of the address, i.e; FE80.
In this blog post, I took an example from only Unicast addresses. Remember, there are also Multicast and Anycast address ranges. Let’s now create some servers and perform some IPv6 configurations.
Goodbye IPv4 and, say Hello to IPv6
I created a CentOS7 machine on my VirtualBox. As you can see, the interface card enp0s8 have the IP Address 192.168.100.9 as well as fe80::9ef3:b9d3:8b87:4940. Remember, the fe80 is the Link Local Address.
You can also see the connection using the following command:
To create a connection using nmcli use the following command and check back the connection. You will notice that the connection has been created without any device attached to it.
I am now modifying ipv6-tunnelix and attached it to enp0s9. I will also assign it to an IPv6 address. (For learning and testing purpose, this IPv6 address has not been assigned to me, it’s that of Facebook’s public IPv6)
As you can see, the address has been assigned. But remember, same as you can assign a public IPv4 address on a virtual machine, you will need to route it for connectivity. In this example, I took an example of Facebook public IP Address.
Getting certified on IPv6 is really interesting as it can demonstrate comprehensibility. You can participate in free IPv6 training and get certified from Hurricane Electric. It is important to read the IPv6 primer.
There is also a service from Hurricane Electric, called Tunnel Broker which can facilitate you for creating a tunnel from your IPv4 static IP address to free IPv6 tunnels. In future blog posts on IPv6, I will get into more details about it. If you like the article, please comment, and share.
Have you ever deleted a logical volume by accident? Can you recover it looking into the backups? Well, the answer is YES. For those who are not familiar with Logical Volume Management (LVM) is a device mapper target that provides logical volume management for the Linux kernel.- Wikipedia. It is an abstraction layer or software that has been placed on top of your hard drive for flexible manipulation of the disk space. Some of the articles published in the past on LVM are:
All test carried out on this blog post have been tested on a CentOS machine. Please don’t make a live test on a production server.
1. So, as you can see below I have an lv called lvopt which is from a vg called centos.
2. Same is mounted on the /opt
3. There are some data in that partition as well:
4. I created a directory inside the /opt directory
5. Now, let’s pretend to remove the lvm lvopt. Or say, someone did it by accident because it was unmounted. The command lvremove will be used here to remove the lv. Note: that the lv need to be unmounted.
6. If you make an lvs, lvdisplay or vgs or even mount again the partition, you cannot do it. The data is lost. But you can still recover it. This is because the lvm contains the archive of your lv inside the folder /etc/lvm/archive. But, you cannot read the files directly.
7. But you can still, interpret part of the files. Since we deleted the volume group called “centos”, we knew that it is referenced in the file centos_… The question that arises here is which file is relevant for you. Right? So to understand which archive you want to restore, you need to use the command vgcfgrestore –list <name of volume group>. Here is an example:
8. If you observe carefully, each archive has been backup at a certain time. In my case, I deleted the LV on 18-Apr-2019 at 11:17:17 2019:
9. So, I want to restore from that last archive. You will need to copy the full patch of the vg file. In my case it is /etc/lvm/archive/centos_00004-1870674349.vg. The goal here is to restore the lv before this specific time, or simply restore back the lv before the command lvremove was fired. Here is the command:
10. If you launch the command lvs, you will notice the presence of the lv.
11. But, mounting back the lv won’t result in anything. This is because the lv is inactive. You can see it with the command lvscan. Please take note below that the lvopt is inactive.
12. To activate it you simply need to use the command lvchange.
13. Mount it back and you are done.
I believe this can be very useful especially when you have encountered a situation where someone deleted an lv. I hope you enjoy this blog post. Please share and comment below if you like it.
A few weeks back, I registered myself to present the Ansible automation tool at the Developers Conference 2019 at Voila Hotel, Bagatelle Mauritius. The event is an initiative of Mauritius Software Craftsmanship Community – MSCC sponsored by several companies such as Mauritius Commercial Bank, SdWorx, Eventstore, Ceridian, Castille, etc. There were other members of cyberstorm.mu who also registered for their presentations: they are Codarren Velvindron, technical lead at Orange Business Services who spoke about “becoming an automation artist”, Loganaden Velvindron who spoke about “RedHat Enterprise Linux 8 and Derivatives have a new Firewall: NFTABLEs”, and Nathan Sunil Mangar who spoke about “Introduction to the STM32”. There was also a special event where Mukom Akong Tamon, head of capacity building for Africa region at Afrinic who spoke on “IPv6 deployment in Mauritius and Africa at large”. I presented myself as a member of cyberstorm.mu and DevOps Engineer at Orange Business Services and spoke on Ansible for beginners with some basic and advanced demos.
In the past, I have written several articles on Ansible:
My presentation started with a basic introduction to Ansible following some brief examples and demos. I started with a brief introduction of myself. It looks like it was a mixed audience including, Students, Professional from the management and technical side, Engineers, and others. I brushed out quickly as to why we need Ansible in our daily life whether for home use or on production. Ansible is compatible with several Operating systems and one of the most interesting tools is the AWX which is an opensource product. Before getting started with Ansible, it is important to grasp some keywords. I introduced it as well as giving some examples using Playbooks. Ansible Ad-hoc commands were also used. The audience was asked to give some ideas about what they want to automate in the future. There were lots of pretty examples. I laid some emphasis on reading the docs and keep in touch with the version of Ansible one is using. Also gave some brief idea about Ansible-Galaxy, Ansible-doc, Ansible-pull, and Ansible-vault. To spice up your automation layout, it would be nice to use Jinja templates, verbosity for better visual comprehension. I also spoke about Ansible-CMDB, which is not a tool of Ansible. Some days back, I blogged on Ansible-CMDB which is pretty interesting to create an inventory. I also shed some ideas about how to modify the source code of Ansible-CMDB. Also, an example using an Ansible Playbook build up web apps.
Thanks, everyone for taking pictures and some recordings.
cyberstorm.mu @ DevConMru
After my session, I went to the Afrinic session on IPv6, where Mukom Akong Tamon was presenting on IPv6 where he brushed out on an introduction to IPv6 and the IPv6 format structure. Also, several examples of why it is important to migrate to IPv6. Loganaden Velvindron from Afrinic enlightened the audience about dual stack programming.
One of the important part where Mr. Mukom mentioned that there are still developers hard coding IP addresses in the code which is not a good practice.
There was another session by Loganaden Velvindron of Afrinic, who spoke on NFtables in RedHat 8. Mukom was also present there in the session. Loganaden explained about NFtables architecture and its advantages. Also explained how to submit patches and dual stack building with NFtables.
Codarren Velvindron, technical lead at Orange Business Services and member of cyberstorm.mu explain why automation is important. He took some example on the conference.mscc.mu website itself. Also gave some ideas using “Expect”. For those who are not familiar with “Expect”, it is a scripting programming language that talks with your interactive programs or script that require user interaction.
Nathan Sunil Mangar also presented on an introduction to the STM32 microcontroller. He also gave some hints to distinguish between fake and real microcontrollers on the market. Apart from the basic introduction, he went brushed out some examples on several projects and explain which one can is better. However, it also depends on the budget when choosing microcontrollers. He also showed how to use the tool of programming for the STM32 microcontroller. The documentation was also perused during the presentation. At the end of the presentation, there were several giveaways by Nathan Mangar including, fans, Microcontrollers, and a small light bulb made from STM32.
I also have the opportunity to meet with several staffs from the Mauritius Commercial Bank who asked for some hints and best practice on Ansible. Also had some conversations with other people in the tech industry such as Kushal Appadu, Senior Linux system Engineer at Linkbynet Indian Ocean. We discussed lengthily on new technologies. Some days back, I presented the technicalities of Automation as a DevOps Engineer at SupInfo university Mauritius under the umbrella of Orange Cloud for Business and Orange Business Service. I was glad to meet a few students of SupInfo at the DevCon 2019 who instantly recognized me and congratulated me for the Ansible session.
I sincerely believe there is still room for improvement at the Developers conference such as the website itself which needs some security improvements. Otherwise, a feature that could be added is to specify which session is for beginners, intermediate or advanced so that attendees can choose better. The rating mechanism which is not based on constructivism might discourage other speakers to come forward next time. But overall, it was a nice event. Someone from the media team filmed me for a one-minute video, hoping to see it on the net in the future. I also got a “Thank You” board for being a speaker by Vanessa Veeramootoo-Chellen, CTO at Extension Interactive and one of the organizers at the Developers conference who can be seen to be always working, busy and on the move during the event.
The AWSome day was a free online Conference and a training event sponsor by Intel that will provide a step-by-step introduction to the core AWS (Amazon Web Services) services. Its free and everyone can attend. It was scheduled on 26 March 2019 online. The agenda covered broad topics such as AWS Cloud Concepts, AWS Core Services, AWS Security, AWS Architecting and AWS Pricing and Support. It’s pretty interesting for IT manager, system engineers, system administrators, and architects who are eager to learn more about cloud computing and how to get started on the AWS cloud. I do have some experience in managing AWS servers and even host my own server. However, I registered for the free training to refresh my knowledge and get more exposure such as the AWS pricing which I am not aware at all. Another interesting thing is that you will receive a certificate of attendance and you received 25 USD of AWS credits. Pretty cool right?
Right from the beginning, I knew this was something interesting. I encountered a minor problem whilst signing in. I had to send a mail to support and it was resolved immediately. Once connected to the lobby, it was pretty easy to attend and follow the online conference. After some minutes, Steven Bryen, head in the AWS Cloud delivered the keynote speech.
There was also an online challenge and I score 25,821 on the Trivia Leaderboard.
The event was pretty enriching. The panel on the question area knows well their subject. I discovered a lot by participating in the AWSomeDay. I’m looking forward to AWS certifications in the near future.