Istio Canary Upgrade: upgrading our Istio from v1.10.x to v1.15.6

Question

We are in the process of upgrading our Istio from v1.10.x to v1.15.6, I have gone through the Canary upgrade document and as per my understandings I can install newer version i.e. v1.15.6 and then switch the revision tags. Is my understanding correct? or I can only perform sequential major upgrades?

warm regards, Suhas

Answer 1

You should only perform one or two sequential minor version upgrades with istio when using canary upgrades.

v1.10.x -> v1.11.x  ok
v1.10.x -> v1.12.x  ok
v1.10.x -> v1.13.x  not recommended

Though it might work, jumping more than two minor versions isn't officially supported and might break things, from docs

Upgrading across more than two minor versions (e.g., 1.6.x to 1.9.x) in one step is not officially tested or recommended.

Without canary upgrade you can only jump one minor version (e.g. 1.10 to 1.11).

So in your case you could do

v1.10.x -> v1.12.x
v1.12.x -> v1.14.x
v1.14.x -> v1.15.x (or 1.16, see comment below)

Note that 1.17 has already been released so you might as well go to 1.17 or at least 1.16 instead of 1.15. Especially with canary upgrade, going to 1.16 is the same effort as going to 1.15.