17. Docker – Swarm

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Docker – Swarm



Docker swarm is a technique to create and maintain cluster of docker engines. One service deployed in any docker engine (node) can be access from other nodes in the same cluster.

තවත් විදිහකට කියනවනම් group of machines that are running Docker and joined in to a cluster.

වෙන වෙනම docker engine install කරලා තියන machine එහෙම නැත්තම් node එකින් එක connect කරගෙන docker manager කියලා කෙනෙක් හරහා ඒවා manage කරගන්න එක තමයි මෙහිදී වෙන්නේ.



Manager basically initialize the whale swarm. Load balnce කරන්නේ මෙයා.Manger is the heart of the docker cluster.

Why is docker swarm?

High availability – එක node එකක් down වුනාට අවුලක් වෙන්නේ නැ වෙන එකකට a reuquest එක යවලා වැඩේ කරවලා දෙනවා.

Auto load balancing - scaling කරගනිද්දී එමක service එක node කිහිපයකම run වන නිසා, load එක auto ම balance කරලා එක  node එකකට request එක යවනවා.

Decentralized access – එක එක තැන් වල deploy වෙලා තියන නිසා(node එක එක තැන් වල තමා තියෙන්නේ) ඒක manager හරහා ඕන තැනක ඉදන් access කරන්න පුළුවන් වෙනවා.

Easy to scale up – එක node එකක run කරන්න පුළුවන් services limit එකක් තියනවා,ඊට වඩා දැම්මොත් recourse මදි වෙලා අවුල් වෙනවා. ඒ වගේ අවස්ථාවන්ට වෙන වෙන  ඒවගේ එම service එක host කරවන්න පුළුවන් වෙනවා.

Rolling update -service update කරද්දී ඔක්කොම node වල ඒවා down වෙන්නේ නැතුව එකක් උනාම  අනෙත් එක update කරනවා වගේ කරන්න පුළුවන්.




ඉහත image එකේ පළමු command එක run කරන්නේ manager create කරන්න වන අතර,ip-addr යනු manager ගේ IP address එක වේ.මෙම command එක run කලාම token එකක් provide කරන  අතර එම token එක හරහාඅනෙත් node වලට manage හදපු මෙම cluster එකට connect වෙන්න වේ.එම image එකේ මුල් command set එක docker manager node එකේ පමණක් run කල හැක.එනම් manner ට පමණක් අදාල ඒවා වේ.

Manager :


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