WEBVTT - This file was automatically generated by VIMEO 0 00:00:00.200 --> 00:00:03.600 Hello and welcome to this lecture. This is a quick introduction to 1 00:00:03.200 --> 00:00:06.400 Etsy for beginners. If you already know 2 00:00:06.400 --> 00:00:09.300 about hcd feel free to skip this video and head 3 00:00:09.300 --> 00:00:12.500 over to the next video where we discuss about etsad in 4 00:00:12.500 --> 00:00:13.000 kubernetes. 5 00:00:13.600 --> 00:00:16.300 We start with a basic introduction to what a key 6 00:00:16.300 --> 00:00:20.100 value story is and how it is different from traditional databases how 7 00:00:19.100 --> 00:00:22.000 to quickly get started with hcd and how 8 00:00:22.100 --> 00:00:24.800 to use the client tool to operate at CV. 9 00:00:25.500 --> 00:00:28.700 Later in this course when we cover High availability. We 10 00:00:28.700 --> 00:00:31.500 will discuss about what it means to be a distributed system. 11 00:00:31.500 --> 00:00:34.800 How at City Works in a cluster mode what raft 12 00:00:34.800 --> 00:00:37.200 protocol is and what are the best practices around the 13 00:00:37.200 --> 00:00:39.100 number of nodes in an hcd cluster? 14 00:00:40.400 --> 00:00:41.800 So what is hcd? 15 00:00:42.400 --> 00:00:45.600 It is a distributed reliable key value store 16 00:00:45.600 --> 00:00:47.700 that is simple secure and fast. 17 00:00:48.400 --> 00:00:49.400 So let's break it up. 18 00:00:50.200 --> 00:00:54.300 So what is a key Value Store traditionally databases 19 00:00:53.300 --> 00:00:56.400 have been in a tabular format? You must 20 00:00:56.400 --> 00:01:00.300 have heard about SQL or relational databases the 21 00:00:59.300 --> 00:01:02.200 store data in the form of rows and 22 00:01:02.200 --> 00:01:02.800 columns. 23 00:01:03.400 --> 00:01:06.600 For example here is a table that stores information regarding 24 00:01:06.600 --> 00:01:07.600 few individuals. 25 00:01:08.400 --> 00:01:11.700 The row represents each person and the column represents 26 00:01:11.700 --> 00:01:13.700 the type of information being stored. 27 00:01:14.400 --> 00:01:18.300 Now say we want to add additional details about this individuals. Say 28 00:01:17.300 --> 00:01:20.200 for example salary, so we add 29 00:01:20.200 --> 00:01:21.200 an additional column. 30 00:01:22.300 --> 00:01:25.100 Doing so impacts the entire table and all of 31 00:01:25.100 --> 00:01:26.400 the individuals in them. 32 00:01:26.900 --> 00:01:29.300 We then add salary details to this column. 33 00:01:29.900 --> 00:01:32.100 However, not all of them are working. 34 00:01:32.900 --> 00:01:34.600 So those cells remain empty? 35 00:01:35.500 --> 00:01:38.500 We're then required to store great information. So 36 00:01:38.500 --> 00:01:41.500 we add a new column and update these students with 37 00:01:41.500 --> 00:01:44.500 their respective grades again, only students 38 00:01:44.500 --> 00:01:47.500 have grades. So the corresponding fields for adults 39 00:01:47.500 --> 00:01:48.100 are empty. 40 00:01:48.800 --> 00:01:51.600 Every time a new information needs to be added. The 41 00:01:51.600 --> 00:01:54.400 entire table is affected and leads to 42 00:01:54.400 --> 00:01:56.100 a lot of empty cells. 43 00:01:56.900 --> 00:01:59.600 A key Value Store stores information in 44 00:01:59.600 --> 00:02:02.300 the form of documents or pages. So each 45 00:02:02.300 --> 00:02:05.400 individual gets a document and all information 46 00:02:05.400 --> 00:02:08.800 about that individual is stored within that file. 47 00:02:09.800 --> 00:02:12.500 These files can be in any format or structure 48 00:02:12.500 --> 00:02:15.200 and changes to one file does not affect the others. 49 00:02:16.200 --> 00:02:19.400 The working individuals can have their files with salary fields and 50 00:02:19.400 --> 00:02:22.400 the students can have their pages with grades only. 51 00:02:23.400 --> 00:02:26.500 You can add additional details to any of these documents without 52 00:02:26.500 --> 00:02:28.800 having to update other similar documents. 53 00:02:30.400 --> 00:02:33.400 While you could store and retrieve simple key and values 54 00:02:33.400 --> 00:02:36.400 when your data gets complex, you typically 55 00:02:36.400 --> 00:02:39.500 end up transacting in data formats like Json 56 00:02:39.500 --> 00:02:40.300 or ammo. 57 00:02:41.600 --> 00:02:44.200 It's easy to install and get started with etcd 58 00:02:44.200 --> 00:02:47.300 download the binary extracted and run. 59 00:02:48.100 --> 00:02:51.400 Download the relevant binary of four you operating system from the 60 00:02:51.400 --> 00:02:54.200 GitHub release Pages extracted and 61 00:02:54.200 --> 00:02:55.800 run the hcd executable. 62 00:02:56.400 --> 00:02:59.300 When you run hcd it starts a service 63 00:02:59.300 --> 00:03:02.500 that listens on Port 2379 by default. 64 00:03:02.500 --> 00:03:05.700 You can then attach any clients to the Etsy 65 00:03:05.700 --> 00:03:07.900 service to store and retrieve information. 66 00:03:08.800 --> 00:03:11.700 A default client that comes with LCD is 67 00:03:11.700 --> 00:03:13.200 the LCD control client. 68 00:03:13.900 --> 00:03:16.400 The hcd control client is a command line 69 00:03:16.400 --> 00:03:19.900 client for hcd you can use it to store and retrieve 70 00:03:19.900 --> 00:03:20.900 key value pairs. 71 00:03:21.400 --> 00:03:24.600 To store a key value pair run the LCD control 72 00:03:24.600 --> 00:03:27.500 set key one command followed by the value 73 00:03:27.500 --> 00:03:30.400 value 1 this creates an entry 74 00:03:30.400 --> 00:03:31.800 in the database with the information. 75 00:03:32.900 --> 00:03:35.000 To retrieve the store data run the 76 00:03:35.900 --> 00:03:37.900 LCD control getkey1 command. 77 00:03:38.800 --> 00:03:41.300 To view more options run the hcd control 78 00:03:41.300 --> 00:03:42.800 command without any arguments. 79 00:03:43.700 --> 00:03:46.900 You might come across different versions of commands while exploring LCD 80 00:03:46.900 --> 00:03:49.400 and related articles online. So it's important to understand 81 00:03:49.400 --> 00:03:52.700 the history of hcd releases. So, you know, what changed 82 00:03:52.700 --> 00:03:53.100 when 83 00:03:53.700 --> 00:03:56.900 So the first version of hcd versions 0.1 84 00:03:56.900 --> 00:03:59.800 was released in August 2013. The official 85 00:03:59.800 --> 00:04:02.700 stable version 2.0 was released 86 00:04:02.700 --> 00:04:05.700 in February 2015. And 87 00:04:05.700 --> 00:04:08.700 this is when the raft consensus algorithm was 88 00:04:08.700 --> 00:04:12.300 really designed and it's supported more than 10,000 rides 89 00:04:11.300 --> 00:04:15.100 per second and in January 2017 90 00:04:14.100 --> 00:04:18.000 at CD released version 3 with 91 00:04:17.100 --> 00:04:20.600 a lot more optimizations and performance improvements. 92 00:04:21.400 --> 00:04:24.400 And finally in November 2018, that's 93 00:04:24.400 --> 00:04:28.300 when the STD project I was incubated in cncf. 94 00:04:29.400 --> 00:04:32.600 So what's most important here is to note the 95 00:04:32.600 --> 00:04:35.900 change between version 2 and version 3 so 96 00:04:35.900 --> 00:04:38.700 version 2 had been used a lot 97 00:04:38.700 --> 00:04:41.600 and with version 3 there 98 00:04:41.600 --> 00:04:44.600 were a lot of changes made. So the API version's changed 99 00:04:44.600 --> 00:04:47.200 between version 2 and version 3 so that means 100 00:04:47.200 --> 00:04:50.100 the HD cuddle commands change as well. So that's what I'm 101 00:04:50.100 --> 00:04:50.500 going to talk about. 102 00:04:51.600 --> 00:04:52.200 next 103 00:04:53.100 --> 00:04:56.500 so the set and get commands. I showed earlier where for version 2 and 104 00:04:56.500 --> 00:04:59.400 1 work for version 3 your hcd cuddle 105 00:04:59.400 --> 00:05:02.900 command is configured to work with V2 and V3 106 00:05:02.900 --> 00:05:03.800 at the same time. 107 00:05:05.500 --> 00:05:08.500 So how do you find out what version at cdcudl is 108 00:05:08.500 --> 00:05:11.800 configured to work with run the LCD cuddle 109 00:05:11.800 --> 00:05:14.100 version command and it should tell 110 00:05:14.100 --> 00:05:17.400 you if it's said to V2 or V3 now in this output, you 111 00:05:17.400 --> 00:05:20.700 can see the actually cuddle version itself, which is V3. So 112 00:05:20.700 --> 00:05:23.300 that's the first line. However, the API version 113 00:05:23.300 --> 00:05:26.600 is too. So remember that there are two types of 114 00:05:26.600 --> 00:05:29.500 versions. So one is the LCD cuddle utility itself. And 115 00:05:29.500 --> 00:05:32.200 the other is the API that it is configured to 116 00:05:32.200 --> 00:05:35.500 work with which will either be two or three. So this means in 117 00:05:35.500 --> 00:05:38.300 the current state it means that it's configured to work with 118 00:05:38.300 --> 00:05:41.500 V2. And so if you run the LCD cuddle 119 00:05:41.500 --> 00:05:44.500 command without any options, then it lists 120 00:05:44.500 --> 00:05:47.700 all the commands that it supports and these are for version two 121 00:05:47.700 --> 00:05:50.300 and note that with newer versions 122 00:05:50.300 --> 00:05:53.300 of etsy. The default. API version is set to 123 00:05:53.300 --> 00:05:56.400 read three so you might want to check what version it 124 00:05:56.400 --> 00:06:00.200 is set to using this version command before starting to 125 00:06:00.200 --> 00:06:02.300 run the city commands. 126 00:06:03.400 --> 00:06:06.300 So to change HD cuddle to work with 127 00:06:06.300 --> 00:06:09.300 the API version 3 either set the environment 128 00:06:09.300 --> 00:06:12.300 variable called Etsy cuddle underscore API 129 00:06:12.300 --> 00:06:15.200 to three for each command. So right before 130 00:06:15.200 --> 00:06:18.100 you run the command or you can export it as 131 00:06:18.100 --> 00:06:21.100 an environment variable for the entire session using the export command. 132 00:06:21.100 --> 00:06:24.300 So that way you don't have to add it before each 133 00:06:24.300 --> 00:06:28.000 time. The command is run now also note that with we 134 00:06:27.200 --> 00:06:30.400 three version is now a command and 135 00:06:30.400 --> 00:06:33.500 not an option as it was with we too 136 00:06:33.500 --> 00:06:36.800 so in V2 you had to run Dash version and 137 00:06:36.800 --> 00:06:39.300 now so that was an option now, it's a command so 138 00:06:39.300 --> 00:06:40.000 you just run version. 139 00:06:40.800 --> 00:06:43.300 now running STD cuddle command now 140 00:06:43.300 --> 00:06:46.500 lists the command in the API version 141 00:06:46.500 --> 00:06:47.700 3 142 00:06:49.700 --> 00:06:52.700 So with version 3 now the command 143 00:06:52.700 --> 00:06:55.500 to set a value is Etsy cuddle put 144 00:06:55.500 --> 00:06:58.800 and the command to get a value 145 00:06:58.800 --> 00:07:01.200 is Etsy cuddle get 146 00:07:01.200 --> 00:07:04.800 and there are many other changes as well in a 147 00:07:04.800 --> 00:07:07.400 number of other commands, but that's kind 148 00:07:07.400 --> 00:07:10.400 of a high level on how it CD Works in a city 149 00:07:10.400 --> 00:07:13.700 cuddle works. All right, so that's that's all for now in a 150 00:07:13.700 --> 00:07:16.400 later video. We will explore how to set up HD in 151 00:07:16.400 --> 00:07:19.900 an ha environment and how it works with kubernetes. So thanks 152 00:07:19.900 --> 00:07:21.900 for watching and I'll see you in the next one.