I've recently been thinking about my SRE journey and the SRE role I had at Twitter. When I joined in 2015, it was my first SRE titled position but I frankly didn't know what the SRE job was really all about.
At the time, Twitter had no specific SRE onboarding - Flight School was focused on software engineers. You were mostly expected to shoulder-surf existing SREs and learn by osmosis and that's what I did. That's a poor approach in multiple ways including how it is unstructured, requires extensive one-to-one time and may not suit the learning style.
Instead, I used the approach of "to learn it, teach it" and I started creating some SRE-specific onboarding along with an experienced SRE colleague, Rob Malchow. Over a year or so, we developed 3 SRE onboarding courses that covered technologies, processes and specific help for SREs in particular about how to prepare and be oncall - including a big DON'T PANIC slide.
I taught this series of 3 courses with Rob and others maybe 5 times to hundreds of people and every time I tried to invite an existing experienced SRE to join, so that every time the course material was improved and corrected, because nothing stays still in tech. I also believe that pair or co-teaching works much better as two people can both deliver and check for understanding in parallel. At the end I felt I had got a good grasp of the SRE scope. Hopefully the students did too!
With reference to the SRE books from Google, I had read the first one which was out at the time but I found that Google scale and approaches needed customizing for the environment although lots was highly relevant to get to a data-driven approach to reliability using SLA, SLI, SLOs and error budgets.
Now I'm at Google and can see the other side of the fence, where SRE training ("SRE EDU") is taken very seriously and extensive training created and delivered where feedback and evolution is built in. Education remains a very interesting area to me and "always be learning" is an important value of mine. It's also a key part of being an SRE, and working in tech more generally. Hopefully I can participate here too.