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Hey everyone and welcome back. Now in the previous nugget we had just introduced the

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concept of NFS, we learned how it was different although maybe similar to SAMBA, in that we

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can ultimately share resources but what we're going to be focusing on is actually sharing

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file systems and we understood that within this architecture we would have to configure

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an NFS server. That is exactly what we're going to be focusing on in this nugget right

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here. So with that said let's roll up our sleeves and dig in then share with. So what

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I will do here is I will clear my screen right now and the very first thing which I am going

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to do is I am going to install a particular package. Now this package here I'm going to

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say sudo and I will say apt install and I will say nfs- and I was going to say server

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it's not server it's hyphen kernel hyphen server. I'm getting myself confused here.

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If I hit enter and I type in my password right here all I'll do is say yes and hit enter and

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the installation should now begin. Okay so as we can see here everything has installed

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correctly. Now that we have this the very first thing which I want to draw your attention

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to and if I just clear my screen right now the very first thing is going to be in the

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etsy directory there is going to be a file called exports. This is going to be the main

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configuration file for NFS. As per usual with respect to the LPIC2 examination remembering

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this location is certainly going to serve you well. Really within this configuration

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file this is where we are going to specify what it is we want to share and who we want

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to grant access to this share as well as like I say the permissions of what that particular

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client can do with that particular share. All of that specified within this etsy export

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file right here and in fact I've just caught myself that should be etsy exports with an

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s on the end so really just remember that there almost made that mistake myself. So

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check this out then if I clear my screen once again and I go into my etsy directory I do

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an LS and I grant for exp. We can see we have indeed this file right here within the etsy

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directory so let's go in and edit this file so we'll go into the etsy directory and open

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exports. Now we can see here this is going to be the access control list for file systems

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which may actually be exported when you're using NFS ultimately dictating what our NFS

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clients can actually have access to. So remember as I mentioned what we want to do here is

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we want to specify what it is you want to share who we want to share that with and then

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in the brackets we want to specify the rules for that share i.e. what that person can actually

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do with that share. Now with respect to what we can actually specify within this configuration

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file there are a few different things. We can specify a particular hostname of a device

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i.e. we had a particular hostname on our network we wanted to grant access to we could actually

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use that hostname and grant that particular access. We could also specify something let's

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say the domain i.e. the particular domain name for a group of devices maybe we've got a domain

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such as CBTNuggets.com and we want to grant access to all machines within that domain we could

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specify that domain within this configuration file or alternatively if we so wish we could specify

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a particular network say for example we want to allow everyone within 192.168.1.0 slash 24 we

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wanted to grant them particular access we could do so and within here we can also specify should

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the share be ro i.e. should that share be read only meaning that the people can read the information

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that we're sharing but they cannot create new files nor can they modify existing files or

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alternatively you guessed that we could specify rw access read and write access meaning that we can

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read and we can also create and modify files. Now we can also specify if we want to sync our

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changes this means that whatever changes happen to be made within the share they are going to be

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synced and written to the hard disk without any delay at all they're going to happen immediately

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so those changes get synced quickly however we can specify a sync which means that changes to a

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file system will not be made immediately instead those changes will be held in RAM now the advantage

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here is that this is going to give you better performance it's going to be less taxing on the

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machine to be writing and reading data from the disk just by holding it in memory the issue as you

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can probably imagine is that when you hold data within RAM that data happens to be volatile i.e.

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if the machine happened to crash and not correctly shut down or save the information which was held

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in RAM can ultimately be wiped meaning that those changes can be lost this is a trade-off that we

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have to consider do we want to have our changes be synced and immediately written to disk or do we

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want to prefer the performance boost which may be valuable if we happen to have a large distributed

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network all accessing a particular share maybe we want to aim for performance but run the risk of

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potentially losing that data or losing some of that data whilst it is temporarily held in RAM

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these are different options that we can consider now one big option we really want to be aware of

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and we'll get to see this in a little bit more detail a little bit later on but ultimately we

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have this problem here imagine we have our server here okay and then we have a client machine all

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the way over here now as you know on your machine you're going to have a default root user this is

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the super user who can do absolutely everything to that particular machine and likewise on the server

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we're going to have that default root user too think about this when this server here is sharing

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out a particular file system let's just maybe say within the mount directory we've got a file

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system called i don't know fs1 whatever it may be doesn't actually matter this file system fs1 is going

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to be transparently available on this machine right here it's going to appear like it actually exists

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on the client even though it's been reached over the network now we know we have this root user here

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on this machine now the question is the files within this particular directory here actually

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physically exist on this machine where we have another root user now the question is do we want

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this root user to have the exact same level of access and control as the actual root user on the

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server now typically most people want to say no most people will pretty much say that okay we have

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a root user on this machine here but we don't want to just transfer that ability of total power

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to be able to execute within that share on the local system we want to have the root user on the

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server itself still maintain that control in which case we actually have two different options here

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and these are options again that we specify within this particular file those options happen to be

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the first one is something called root squash so really if you do not want the remote root user

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to have the same access as the root user within the local server you actually want to configure

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this option i like to try to remember this as we are squashing the ability of the

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remote client root user from being able to have total access however if we actually do want to

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synchronize these root users i.e. we want the root user and the clients to be able to act with the

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same type of authority as the local root account on the server itself we can synchronize these

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root accounts so to speak and we can do so by specifying the option no underscore root underscore

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squash so we can either squash the ability of the remote root user on the client or we can say we

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do not want to squash that ability we can give them full access and full control all of these

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options that we've seen here again specified within this file right here so with that said

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let's actually create our own little share and begin using nfs then so what i will do here is i'm

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going to create a share and i'll just call this my share again you know me never ever in danger of

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being creative so so what i will do is i will move on over and what i now want to specify is who can

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actually have access so what i can do here is i could say 192 168 maybe 0.100 let's say this was

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a particular machine on the network and i wanted to allow access to that particular machine so what

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i could do here is within brackets i could specify my permission so i could say that machine is allowed

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to have read only access and when that machine connects i want to implement the root squash option

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i.e the root user of that machine will not be able to execute within this particular directory as if

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it was the root user of the local machine where the physical data actually resides let me just close

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that space here so that is one way we could specify some information now let's say we wanted to add

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additional information so right now we have rules for this particular host right here remember we

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can specify a host but we can also specify as we discussed other things such as a particular network

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so let's maybe say i wanted to say 192 168 50.0 slash 24 anyone on this network they are also going

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to get access but people on that network are going to get read write access so they can actually make

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changes not only that but also can specify in this case here we'll say no root squash i.e the root

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users will be able to operate like they were the root user on the local server and again as we can

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see here the format as i specify this is the share this is who is allowed to access the share

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and under what conditions can they access that share again who can access and what conditions

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they have access to this share now one thing to say here is that this is not the only way we can

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specify particular access we can actually access or allow access by using things such as wildcards

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so what i could even do here is i could just specify a star for example in fact let me just

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not mash the keypad and just do a star and within here i can say rw and root squash for example so

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all i am actually saying here is that anyone who tries to access this particular share i'm going

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to allow it and i'm going to allow them to do so with read write access but invoke the root squash

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option so understand we can specify hosts we can specify networks we can even use wildcards lots

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of flexibility right here but for now what i will do here is i will allow access to anyone within the

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192 1680.0 network which is my own network with a slash 24 and i'll grant access to my share so i

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actually have to be able to create this so i'll save this and exit out and just like we saw with

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respect to our samba configuration let's go back to the home directory in fact i'll go into the root

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directory because that's what it's going to be i'll say sudo mkdir and i will create my share type in

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my password right here to an ls-l we can now see my share let's actually grant the full permission

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so we'll say all the sevens on my share so now what i want to do is i want to start up this server

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i will say sudo system ctl and i will start the nfs kernel hyphen server and i will now say sudo

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system ctl status of the nfs kernel server we can now see that this is active now what i want to show

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you is a very very important command this is a command we absolutely want to be remembering for

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the purposes of the examination and this is the export fs command what this is going to do is going

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to allow us to see what the server actually is sharing so if i say man export fs we can see here

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this is going to maintain a table of the exported nfs file systems so if i scroll on down we can see

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these different options we have available to us notice here that if i use the dash a flag we're

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going to either export or unexport all the directories we can use the dash o option to specify a list

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of export options we can actually choose to ignore the contents of our exports file but one i want

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to really look at is this dash r flag this is going to allow me to reread ultimately what is

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within the contents of the xa exports file ie the changes we just made we can reread them in

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and then they should be shared out so if i say sudo exports fs we don't actually see anything right

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now but if i reread that file in and use dash r the file has now been read in we now see we actually

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have a configuration for my share the share that we just created okay and we're actually granting

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access to this particular network so if i rerun this command we can now see indeed

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that this particular share is accessible to this particular network or devices within

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that particular network similarly what i could also say is sudo show mounts and use dash e to

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show my exports and then i can specify my own ip address so in fact let me just double check my

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ip address right here happens to be 192 1680.44 so i'll say sudo show mount dash e on my address

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0.44 and we can actually see here the export list for this particular server here is the share and

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here is who is allowed to access that share this particular network now another command we want to

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be aware of is the nfs stat command so if i go in and do man nfs stat we can see here this is going

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to allow us to see nfs statistics and we can see here we have different options we can do dash s

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to see only server side stats or dash c to see client side stats and a whole bunch of other

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options say for example the dash m option or dash dash mounts ie this will print information about

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every one of those mounted nfs file systems or as we can see dash r to see the rpc statistics this

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is the remote procedure call which is facilitating this communication and there are more options to

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see yet again so if i say sudo nfs stat dash s we can see server stats again nothing has actually

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been happening or dash c we do not have any client statistics but understand that when we happen to

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be using this particular feature i.e we are getting particular calls to the server these

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values will increment and then when we happen to have actual clients making these requests we can

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actually query these particular client statistics as of right now we do not have any clients in

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action so for now that is our basic configuration for our nfs server like i say we do not have any

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client configuration up and running quite just yet that is what we're going to be looking at in the

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very next nuggets i hope this has been informative for you and i'd like to thank you for viewing

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you