It's been a big year for open-source software. Microsoft bought GitHub. IBM bought Red Hat. Elastic went public. Cloudera and Hortonworks merged. Now another open-source company is getting a big vote of confidence. Start-up HashiCorp announced Thursday that investors have joined in on $100 million funding round valuing the company at $1.9 billion. HashiCorp — sometimes referred to informally as Hashi, Japanese for "bridge" and a reference to founder and chief technology officer Mitchell Hashimoto — isn't public, and it's not a household name. But the company has been gaining traction.